To see the other types of publications on this topic, follow the link: Vickers hardness (VHN).
Journal articles on the topic 'Vickers hardness (VHN)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Vickers hardness (VHN).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Malau, Viktor, and Latif Arifudin. "Vickers Microhardness Dependence Load and Determining of Tensile Strength of HQ 705 Steel from Microhardness Curves." Applied Mechanics and Materials 842 (June 2016): 43–52. http://dx.doi.org/10.4028/www.scientific.net/amm.842.43.
Full textAbstract:
Vickers microindentation hardness test has been applied for a long time to determine the mechanical properties of a small volume of samples. The procedure of this hardness test consists of using a constant load on a rigid indenter and measuring the dimensions of the indenter residual impression (indentation imprint) on the surface of the sample tested after loading and unloading. The objective of this research is to characterize the mechanical properties and material constants of HQ (High Quality) 705 alloy steel mainly its VHN (Vickers Hardness Number) and tensile strength before and after quenching and tempering heat treatments. The characterization is based on Vickers microhardness dependence load curves.Quenching treatment was performed in a furnace by heating the samples at austenite temperature of 850 o C with holding time of two hours and then the samples were rapidly cooled in oil bath. Tempering processes were conducted by heating again the quenching samples to temperatures of 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 o C with holding time of two hours for each sample. Finally, all samples were slowly cooled in atmospheric temperature. The mechanical properties of samples were characterized by using Vickers microhardness dependence load curves.The results show that VHN (Vickers Hardness Number) depends on indentation load and VHN increases with increment of load for indentation load lower than 5 N. VHN is almost constant for indentation load greater than 5 N. The raw material (without heat treatment) has the VHN and tensile strength of 3413 MPa and 1050.61 MPa respectively and the quenched samples have the VHN and tensile strength of 5407 and 1861 MPa respectively. The Vickers hardness and tensile strength decrease with the increment of tempering temperatures. The higher tempering temperature produces lower hardness and tensile strength. The raw material tensile strength of 1058.8 MPa obtained by tensile test is comparable to its tensile strength of 1050.61 MPa obtained by Vickers indentation. This result indicates that Vickers microindentation is valid to use for evaluating the tensile strength of HQ 705 alloy steel.
2
Rocha, Sicknan Soares da, Gelson Luis Adabo, Guilherme Elias Pessanha Henriques, and Mauro Antônio de Arruda Nóbilo. "Vickers hardness of cast commercially pure titanium and Ti-6Al-4V alloy submitted to heat treatments." Brazilian Dental Journal 17, no. 2 (2006): 126–29. http://dx.doi.org/10.1590/s0103-64402006000200008.
Full textAbstract:
The purpose of this study was to evaluate the effect of heat treatments on the Vickers hardness of commercially pure titanium and Ti-6Al-4V castalloys. Six-millimeter-diameter cylindrical specimens were cast in a Rematitan System. Commercially pure titanium and Ti-6Al-4V alloy specimens were randomly assigned to 3 groups (n=10) that received the following heat treatments: control (no heat treatment); treatment 1 (T1): heating at 750ºC for 2 h; and treatment 2 (T2): annealing at 955ºC for 1 h and aging at 620ºC for 2 h. After heat treatments, the specimens were embedded in acrylic resin and their surface was ground and polished and hardness was measured. Vickers hardness means (VHN) and standard deviations were analyzed statistically by Kruskal-Wallis test at 5% significance level. For commercially pure titanium, Vickers hardness means of group T2 (259.90 VHN) was significantly higher than those of the other groups (control - 200.26 VHN and T1 - 202.23 VHN), which presented similar hardness means to each other (p>0.05). For Ti-6Al-4V alloy, statistically significant differences were observed among the three groups: T2 (369.08 VHN), T1 (351.94 VHN) and control (340.51 VHN) (p<0.05). The results demonstrated different hardness of CP Ti and Ti-6Al-4V when different heat treatments were used. For CP Ti, VHN means of T2 group was remarkably higher than those of control and T1 group, which showed similar VHN means to each other. For Ti-6Al-4V alloy, however, VHN means recorded for each group may be presented as follows: T2>T1>control.
3
Djustiana, Nina, Mitha Amaranila, Nadia Greviana, Myrna Nurlatifah Zakaria, Sunarso, and Arief Cahyanto. "Hardness Evaluation of Carbonate Apatite Cement Based on Various Ratio of Precursor." Key Engineering Materials 758 (November 2017): 52–55. http://dx.doi.org/10.4028/www.scientific.net/kem.758.52.
Full textAbstract:
Carbonate Apatite (CO3Ap) cement is considered as an ideal bone substitute due to its biocompatibility and osteoconductivity. Also, CO3Ap cement has the chemical composition that closes to natural bone. During cement preparation, precursors play an important role that affects the properties of CO3Ap cement. Cement hardness is one of the important properties that need to be evaluated before the obtained cement can be applied as a bone substitute. Therefore, the purpose of this study is to determine the effect of precursor ratio of CaCO3 and CaHPO4 on the hardness level of CO3Ap cement. In the present study, the CO3Ap cement was prepared from CaCO3 and CaHPO4. Both Commercial and synthesized CaCO3 were used. The CO3Ap cement obtained from commercial CaCO3 was used as a control group. Synthesized CaCO3 was obtained from Indonesian natural limestone. Three different CaCO3:CaHPO4 ratios, 40:60, 30:70 and 20:80 were mixed with 1 mol/L Na2HPO4. Samples were kept at 37°C with 100% relative humidity for 24 hours then tested using micro Vickers hardness testing machine. The micro Vickers hardness of the control group with CaCO3:CaHPO4 ratio of 40:60, 30:70 and 20:80 were 5.09 VHN, 6.34 VHN, and 6.73 VHN, respectively. Meanwhile, the micro Vickers hardness of the CO3Ap cement obtained from synthesized CaCO3 were 6.22 VHN, 7.50 VHN, and 10.37 VHN for the CaCO3:CaHPO4 ratio of 40:60, 30:70 and 20:80, respectively. The micro Vickers hardness level of CO3Ap cement precursor ratio from the lowest to the highest was 40:60 < 30:70 < 20:80. In conclusion, the precursor ratio significantly affects the hardness level of the CO3Ap cement. The hardness level of CO3Ap cement obtained from synthesized CaCO3 was higher compared with that obtained from commercial CaCO3.
4
Napitupulu, Richard A. M., Suriady Sihombing, Charles Manurung, and Jonner Togatorop. "Pengaruh Waktu Tahan Dan Penambahan Kadar Garam Dapur (NaCl) Dalam Media Pendingin Air Pada Proses Hardening Terhadap Sifat Mekanik Dan Struktur Mikro Baja Karbon Rendah." SPROCKET JOURNAL OF MECHANICAL ENGINEERING 1, no. 1 (August 9, 2019): 24–33. http://dx.doi.org/10.36655/sproket.v1i1.36.
Full textAbstract:
This study aims to determine the effect of salt (NaCl) in water cooling media with different levels of 10%, 16% and 25% against the hardness level of low carbon steel tested with Vickers after hardening in the hardening process and to determine the proportion of media which coolant produces the highest hardness from the use of water cooling media which is added to different levels of NaCl.
The independent variable in this study is the amount of salt (NaCl) dissolved in water cooling media with different percentages, namely 10%, 16% and 25%. While the dependent variable is the value of the hardness of the material tested with Vickers. Hardness in the hardening process with water cooling media which added different salt (NaCl), 10%, 16% and 25% is 185.02 VHN, 229 VHN and 284 VHN. From the results of the study it was found that there was an effect of the salt content (NaCl) in the water cooling media on the level of hardness in the hardening process of low carbon steel. Higher level of salt will increase value of hardness. The highest hardness was achieved in cooling media with a concentration of 25% NaCl that is equal to 284 VHN followed by cooling media with a concentration of 16% NaCl of 229 VHN and the lowest was a cooling medium with a concentration of 10% NaCl of 185.02 VHN.
5
Nur Haq, Bagus Supriyadi. "THE EFFECT OF QUENCHING MEDIA VARIATIONS ON MICRO STRUCTURE AND VIOLENCE OF THE S45C STEEL STEEL WELDING RESULTS." Journal of Mechanical Engineering and Vocational Education (JoMEVE) 2, no. 1 (July 3, 2019): 1. http://dx.doi.org/10.20961/jomeve.v2i1.27328.
Full textAbstract:
The purpose of this research is to find out the effect of current on microstructure and hardness value in S45C steel before (raw material) and after welding using Shielded Metal Arc Welding (SMAW). This research using experiment method. The Technique of data analysis using descriptive comparative research. The instruments that used for testing microstructure and hardness is Olympus Metallurgical Microscope and Vickers Hardness Tester. Based on the results of the research conclude that (1) the results of the microstructure testing showed the improved martensite structure after welding. In the raw material, martensite structure didn’t exist but the result of SMAW welding methods using quenching media of water, oil, and air that showed martensite structure was exist. (2) The hardness value of raw material is 232 VHN. The specimen with water media had highest average hardness value that is 411 VHN, oil media had average hardness value that is 308 VHN, air media had lowest average hardness value that is 263 VHN. This research showed that the result of SMAW welding using varying quenching media can changed the microstructure and hardness of S45C steel.
6
Puspitasari, Dewi, Debby Saputera, and Rizky Noor Anisyah. "PERBANDINGAN KEKERASAN RESIN AKRILIK TIPE HEAT CURED PADA PERENDAMAN LARUTAN DESINFEKTAN ALKALIN PEROKSIDA DENGAN EKSTRAK SELEDRI (APIUM GRAVEOLENS L.) 75%)." ODONTO : Dental Journal 3, no. 1 (July 1, 2016): 34. http://dx.doi.org/10.30659/odj.3.1.34-41.
Full textAbstract:
Background: One of the acrylic resins properties is the water absorption that affect on the hardness changes of the acry/ic resins. This /aboratory experiments studied disinfectant Alkaline peroxide and celery (Apium graveolens L.) extract 75% effect on the hardness changes of acry/ic denture base resins materia/. Purpose: This study aims to determine the effect of immersion denture cleanser alkalin peroxide and celery (Apium graveolens L.) extract 75% of the hardness acrylic resin.Methods: The study a pure experimental study with posttest-only with control group design. The study was conducted by immersing heat cured acrylic samples of 30 mm of diameter and 5 mm of thickness in alkaline peroxide, ce/ery (Apium graveo/ens L.) extract 75% and aquades for 5 and 15 days. An Vickers Microhardness Testing Machine using the Vickers indentation technique with (50 gr load for 10s) were used for the hardness changes observationResults: The statistical test used One-way ANOVA and Bonferroni with 0.05 significance degree /eve/. The average va/ue of acry/ic hardness in a/ka/ine peroxide and celery extract 5 days 15.01 VHN and 15.37 VHN, 15 days 13.77 VHN and 14.07 VHN.Conclusion: The resu/t showed no significant difference hardness of acry/ic resins denture base plate after immersion in Alkaline peroxide and celery (Apium graveolens L.) extract 75% for 5 and 15 days.
7
Effendi, Nizam. "STRUKTUR MIKRO DAN KEKERASAN BAJA S45C PADA PENGELASAN SMAW DENGAN VARIASI MEDIA QUENCH." Jurnal Ilmiah Pendidikan Teknik dan Kejuruan 12, no. 1 (January 31, 2019): 30. http://dx.doi.org/10.20961/jiptek.v12i1.28916.
Full textAbstract:
<p>The purpose of this research is to find out the effect of current on microstructure and hardness value in S45C steel before (raw material) and after welding using Shielded Metal Arc Welding (SMAW). This research using experiment method. The Technique of data analysis using descriptive comparative research. The instruments that used for testing microstructure and hardness is Olympus Metallurgical Microscope and Vickers Hardness Tester. Based on the results of the research conclude that (1) the results of the microstructure testing showed the improved martensite structure after welding. In the raw material, martensite structure didn’t exist but the result of SMAW welding methods using quenching media of water, oil, and air that showed martensite structure was exist. (2) The hardness value of raw material is 232 VHN. The specimen with water media had highest average hardness value that is 411 VHN, oil media had average hardness value that is 308 VHN, air media had lowest average hardness value that is 263 VHN. This research showed that the result of SMAW welding using varying quenching media can changed the microstructure and hardness of S45C steel.</p>
8
Stoleriu, Simona, Gianina Iovan, Irina Nica, Galina Pancu, Andrei Victor Sandu, and Sorin Andrian. "The Effect of Heating on Surface Microhardness of Resin-based Materials for Direct Restoration." Materiale Plastice 55, no. 4 (December 30, 2018): 584–89. http://dx.doi.org/10.37358/mp.18.4.5079.
Full textAbstract:
The aim of this study was to evaluate and to compare the surface hardness of three types of resin-based materials used for direct restoration after heating at different temperatures. A giomer (Beautifil II, Shofu Dental), a compomer (Dyract eXtra, Dentsply Sirona) and a hybrid composite resin (Gaenial Posterior, GC Corporation) were selected for this study. Twenty disk-shaped specimens of each material were heated at room temperature (21�C), at 37�C, at 50�C and at 60�C. Vickers microhardness test was performed on top and bottom surfaces using digital microhardness tester (Micro-Vickers Hardness System CV- 400DMTM, CV Instruments Namicon). The top and bottom surfaces VHN was calculated as a mean value of five determinations. Also, the microhardness ratio was calculated by dividing the top mean VHN value by bottom mean VHN value. Increased mean hardness values were recorded after heating, irrespective of resin-based tested materials. The highest hardness values were recorded after heating all three materials at 60�C, followed by the hardness recorded at 50�C, 37�C and 21�C. For top surfaces, the lowest hardness value was recorded in Dyract eXtra group when samples were warmed at room temperature and the highest hardness value was obtained in Beautifil II group when samples where heated at 60�C. For the bottom surfaces, Dyract eXtra specimens heated at 21�C presented the lowest hardness values and Beautifil II samples heated at 60�C presented the highest hardness values. On top and on bottom surfaces Dyract eXtra showed the lowest hardness values, followed by G-aenial Posterior and Beautifil II, irrespective the heating temperature.
9
Kurnia, Sianny Surya Putri, Dede Taufik, Veni Takarini, and Zulia Hasratiningsih. "Sintering Temperature Effect on Hardness of Self-Synthetisized Porcelain Made from Natural Sumatran Sand without Kaolin." Key Engineering Materials 782 (October 2018): 227–32. http://dx.doi.org/10.4028/www.scientific.net/kem.782.227.
Full textAbstract:
Dental porcelain is one of the indirect restoration material with excellent aesthetic properties,on the other hand porcelain hardness frequently causing excessive wear of antagonist teeth. This study aiming to evaluate the effect of sintering temperature on the self-synthesized porcelain hardness. In this experiment, 25 porcelain samples were synthesized using Sumatran sand from Pangaribuan and Belitung regions, with the composition of 65 wt% Pangaribuan feldspar, 25 wt% Belitung silica and 10 wt% potassium salt. The samples were sintered in five different temperatures, which were 1110°C (A), 1120°C (B), 1130°C (C), 1140°C (D), and 1150°C (E). These samples were then invested on 5cm diameter resin each. The hardness was tested using Zwick Roell ZHμ Micro Vickers with 900 gram load for 15 seconds in 5 different indented areas for each sample. The result shows average hardness of 435.8 VHN (A), 461.0 VHN (B), 472.0 VHN (C), 487.6 VHN (D), and 528.7 VHN (E), which were increasing as the sintering temperature increased. Statistic result shows that sintering temperature significantly affected the hardness value of the porcelain (p value < 0.05). In conclusion sintering temperature affects the hardness of self-synthesized porcelain made from Sumatran natural sand without kaolin, although the average hardness of self-synthesized porcelain is still higher than average hardness of teeth enamel.
10
Sumpena, Sumpena, and Wardoyo Wardoyo. "Pengaruh Variasi Temperatur Hardening dan Tempering Paduan AlMgSi-Fe12% Hasil Pengecoran terhadap Kekerasan." Jurnal Engine: Energi, Manufaktur, dan Material 2, no. 1 (May 19, 2018): 26. http://dx.doi.org/10.30588/jeemm.v2i1.357.
Full textAbstract:
<p><em>The purpose of this research is to know the effect of Heat Treatment Hardening-Tempering Alloy AlMgSi–Fe12% foundry result to hardness and toughness. The test was carried out on raw material and material test specimen after obtaining Hardening heat treatment at 600</em>℃ <em>and quenching with SAE 20 oil medium. While Tempering variation at temperature 200</em>℃<em>, temperature 250</em>℃ <em>and temperature 300</em>℃ <em>with detention time for 15 min at each temperature, each heat treatment. Hardness testing method is done by standard micro Vickers test method with 100 gf loading. The result of raw material testing for hardness value is 60,92 VHN. Test results after heat treatment process at temperature 200</em>℃ <em>cause hardness value increased by 63,50 VHN. At temperature 250</em>℃ <em>cause hardness value decreased to 59,94 VHN. At temperature 300</em>℃ <em>cause hardness value increase to 76,98 VHN </em></p>
11
Anhar, Wahyu, Nurwahidah Jamal, and Suprapto Suprapto. "PENGARUH POST-TREATMENT PLASMA CVD LAPISAN DIAMOND-LIKE CARBON TERHADAP SIFAT KEKERASAN PERMUKAAN BAJA AISI 410." ROTOR 10, no. 1 (April 1, 2017): 62. http://dx.doi.org/10.19184/rotor.v10i1.5150.
Full textAbstract:
This study is aimed to determine the effect of post-treatment plasma CVD on diamond-like carbon films of surface hardness AISI 410 steel. Enhancement of surface hardness on AISI 410 can be done with deposition thin layer by plasma CVD, and continued by post-treatment plasma CVD. Mixture of Ar (90%) with CH4 (10%), and He (76%) with CH4 (24%) are used as thin layer material. Deposition parameter of pressure, temperature, and time that been used are 1.6 mbar, 300 °C, and 4 hours, respectively. Furthermore, post-treatment process parameter is used by Ar gas, with pressure of 1 mbar, temperature 300 °C, and variation time of 10, 20, 30 minutes. Surface hardness test is used by Vickers microhardness tester. Cross-section microstructure and chemical compositions are examined by scanning electron microscopy coupled with energy dispersive spectroscopy. Based on surface hardness test, the surface hardness on AISI 410 is increased by post-treatment process. The surface hardness from 232.3 VHN increase to 301.2 VHN is produced by post-treatment of compound Ar-CH4 in 20 minutes. Futhermore, the surface hardness from 1,035.8 VHN increase to 1,743.2 VHN is produced by post-treatment of compound He-CH4 in 30 minutes.
Keywords: Post-treatment, Surface hardness, AISI 410, Ar-CH4, He-CH4
12
Candido, Lucas Miguel, Laiza Maria Grassi Fais, José Mauricio dos Santos Nunes Reis, and Ligia Antunes Pereira Pinelli. "Surface roughness and hardness of yttria stabilized zirconia (Y-TZP) after 10 years of simulated brushing." Revista de Odontologia da UNESP 43, no. 6 (December 2014): 379–83. http://dx.doi.org/10.1590/1807-2577.1049.
Full textAbstract:
Introduction: The Y-TZP zirconia used for prosthetic infrastructure, in some clinical situations, can be exposed to the oral environment. In these situations, a polished surface without changes is extremely important. Objective: The aim of this study was to evaluate the mean roughness (Ra) and Vickers hardness of Y-TZP zirconia (Lava™) after simulating ten years of brushing. Material and method: Thirty-six Y-TZP bar-shaped specimens (20mm X 4mm X 1.2mm) were divided into three groups: storage in distilled water (DW, n=12, control); brushing with distilled water (BDW, n=12) and brushing with distilled water and fluoride toothpaste (BFT, n=12). Brushing was performed using a brushing machine with a soft-bristled toothbrush, simulating 10 years of brushing (878.400 cycles, 100gf). The mean roughness (Ra in μm) and Vickers hardness (VHN) of all specimens were measured twice: before and after the experimental treatment, in profilometer and microhardness tester (500gf, 30 seconds), respectively. Data were analyzed using the two-way ANOVA test (α = 0.05). Result: The interaction between groups was not significant for roughness (p = 0.701) nor for hardness (p = 0.928). The final averages for Ra (μm) were equal to: DW - 0.63; BDW - 0.64; and, BFT - 0.68. The final averages for Vickers hardness (VHN) were: DW - 1301.16; BDW - 1316.60; and, BFT - 1299.58. Conclusion: It was concluded that the brushing with distilled or fluoridated toothpaste was not able to change the roughness and hardness of Y-TZP zirconia used in this study.
13
Ghazali, Muhamad Anas Munawwar, Mohd Azhar Harimon, and Mohammad Sukri Mustapa. "Mechanical Behavior and Microstructural Analysis of Molybdenum-TZM Alloy Subjected to Different Annealing Temperature." JSE Journal of Science and Engineering 1, no. 1 (January 31, 2020): 25–29. http://dx.doi.org/10.30650/jse.v1i1.522.
Full textAbstract:
Mo-TZM alloy is one of the most famous economic molybdenum-based alloys. The percentage of chemical composition in mass of Mo-TZM alloy are Mo-0.5Ti-0.08Zr-0.03C. By adding some Titanium and Zirconium so that the mechanical properties and recrystallization temperature of molybdenum has been corresponding improvement. The purpose of this study is to determine the effect of different annealing temperature on mechanical properties of Mo-TZM alloy. The samples will be heated at two different temperature which are 1000 oC and 1300 oC in 1 hour and 40 minutes to change their microstructure behavior. The mechanical properties of the sample like hardness will be analyzed by using Vickers Micro hardness test. The force applied is 4.903 N and Vickers micro hardness number is 0.5 HVN for 10 second. Then to observe the microstructure changes, optical microscope and Scanning Electron Microscope (SEM) is be used. At annealing temperature 1000 oC, it show values of hardness is 249.54 VHN and the grain boundary size is 0.0898mm. While at annealing temperature 1300 oC, it show the lowest values of hardness which is 243.55 VHN and the highest grain boundary size which is 0.1068 mm. By doing annealing heat treatment it will decreases hardness values and increases the size of grain boundary
14
Azevedo, Andrea, Ana Lucia Machado, Carlos Eduardo Vergani, Eunice Teresinha Giampaolo, and Ana Cláudia Pavarina. "Hardness of denture base and hard chair-side reline acrylic resins." Journal of Applied Oral Science 13, no. 3 (September 2005): 291–95. http://dx.doi.org/10.1590/s1678-77572005000300017.
Full textAbstract:
INTRODUCTION: The hardness of denture base materials may undergo changes due to continued polymerization reaction and water uptake. However, the extent to which these processes affect the hardness of materials is still unclear. OBJECTIVE: In this study, the degree of conversion of two hard chair-side reline resins (Duraliner II-D and Kooliner-K) and one heat-cured acrylic resin (Lucitone 550-L) was evaluated indirectly by measuring the surface hardness. The effect of immersion in water on this property was also analyzed. MATERIALS AND METHODS: After processing following the manufacturers' instructions, specimens (5mm diameter and 2mm thickness) were dry stored at room temperature and the Vickers hardness (VHN) was measured with a hardness tester after 0, 2, 7, 30 and 90 days. Specimens were then immersed in water at 37ºC and hardness was evaluated after the same time intervals. Five specimens were prepared for each material. Data were analyzed by Kruskal-Wallis test (P=.01). RESULTS: When dry stored, material L showed an increase in hardness (P<.01) from 0-day (VHN=23.2) to 30-day (VHN=27.1), after which no significant change was observed. A continuous increase in hardness was observed for material D from 0-day (VHN=4.6) to 90-day dry storage (VHN=7.3). For material K, an increase in hardness was observed up to 7-day (VHN=9.2), and then leveled off (P>.01). After 2-day water storage, all materials showed a significant reduction in hardness (P<.01). CONCLUSION: In general, the hardness of the materials evaluated increased during dry storage and decreased after immersion in water.
15
Wibowo, Irfan Adi, Suharno Suharno, and Indah Widiastuti. "THE EFFECT OF VARIATION OF ELECTRIC CURRENT ON MICRO STRUCTURE AND HARDNESS IN SS400 STEEL WELDING PROCESS USING THE SMAW METHOD." Journal of Mechanical Engineering and Vocational Education (JoMEVE) 1, no. 2 (April 2, 2019): 81. http://dx.doi.org/10.20961/jomeve.v1i2.27226.
Full textAbstract:
<p>The objective of research was to find out the effect of current on microstructure and hardness value in Alloy Steel SS400 before (raw material) and after welding using Shielded Metal Arc Welding (SMAW).</p><p>This research uses experiment methods. Technique of analyzing data used was a descriptive comparative research. The instruments used for testing microstructure and hardness were Olympus Metallurgical Microscope and Vickers Hardness Tester.</p><p>Base on the result of research, it could be concluded that the result of microstructure testing showed the improved ferrite structure after welding. In raw material, ferrite structure seemed to looks evenly, but the result of welding using SMAW welding method with current of I20 A, 130 A, and 140A showed that ferrite structure reduced in each specimen, so that perlite structure was very dominant. The hardness value of hardness result showed the different hardness level. The specimen with current of 140 A had higher hardness level of 231,055 VHN than the specimen with current of 120 A (219.222 VHN) and 130 A (223,333 VHN). The result of hardness testing on raw material was 182,333 VHN. This research showed that the welding using varying current changed microstructure and affected the hardness value of Alloy Steel SS400.</p>
16
Colombo, Marco, Simone Gallo, Claudio Poggio, Vittorio Ricaldone, Carla Renata Arciola, and Andrea Scribante. "New Resin-Based Bulk-Fill Composites: in vitro Evaluation of Micro-Hardness and Depth of Cure as Infection Risk Indexes." Materials 13, no. 6 (March 13, 2020): 1308. http://dx.doi.org/10.3390/ma13061308.
Full textAbstract:
The current in vitro study evaluated the Vickers hardness number (VHN) and hardness ratio of four bulk-fill composites (VisCalor bulk; Admira Fusion x-tra; x-tra fil; and GrandioSO x-tra-Voco, Cuxhaven, Germany) to assess the risk of bacterial colonization in comparison with standard composite materials. Thirty samples were prepared for each group. The VHN of both the external (top) and internal surface (bottom) was determined with a micro-hardness tester (200 g load for 15 s), and the hardness ratio was also calculated for each sample. Subsequently, storage in an acidic soft drink (Coca-Cola, Coca-Cola Company, Milano, Italy) was performed; for each group, 10 samples were stored for 1 day, while another 10 were stored for 7 days and the remaining 10 were kept in water as controls. A significant reduction in VHN was shown for all the groups when comparing the external versus internal side (P < 0.05), although the hardness ratio was greater than 0.80, resulting in an adequate polymerization. Regarding the acid storage, all the groups showed a significant decrease of VHN when compared with the controls, both after 1 day (P < 0.05) and after 7 days (P < 0.001). All the products showed adequate depth of cure without further risk of bacterial colonization. However, acid exposure negatively affected micro-hardness values, which might promote subsequent colonization.
17
Soares, Priscilla Barbosa Ferreira, Sarah Arantes Nunes, Sinésio Domingues Franco, Raphael Rezende Pires, Darceny Zanetta-Barbosa, and Carlos José Soares. "Measurement of Elastic Modulus and Vickers Hardness of Surround Bone Implant Using Dynamic Microindentation - Parameters Definition." Brazilian Dental Journal 25, no. 5 (October 2014): 385–90. http://dx.doi.org/10.1590/0103-6440201300169.
Full textAbstract:
The clinical performance of dental implants is strongly defined by biomechanical principles. The aim of this study was to quantify the Vicker's hardness (VHN) and elastic modulus (E) surround bone to dental implant in different regions, and to discuss the parameters of dynamic microindantion test. Ten cylindrical implants with morse taper interface (Titamax CM, Neodent; 3.5 mm diameter and 7 mm a height) were inserted in rabbit tibia. The mechanical properties were analyzed using microhardness dynamic indenter with 200 mN load and 15 s penetration time. Seven continuous indentations were made distancing 0.08 mm between each other perpendicularly to the implant-bone interface towards the external surface, at the limit of low (Lp) and high implant profile (Hp). Data were analyzed by Student's t-test (a=0.05) to compare the E and VHN values obtained on both regions. Mean and standard deviation of E (GPa) were: Lp. 16.6 ± 1.7, Hp. 17.0 ± 2.5 and VHN (N/mm2): Lp. 12.6 ± 40.8, Hp. 120.1 ± 43.7. No statistical difference was found between bone mechanical properties of high and low profile of the surround bone to implant, demonstrating that the bone characterization homogeneously is pertinent. Dynamic microindantion method proved to be highly useful in the characterization of the individual peri-implant bone tissue.
18
Deniz Arısu, Hacer, Evrim Eligüzeloglu Dalkilic, Fehime Alkan, Sebnem Erol, Mine Betul Uctasli, and Alican Cebi. "Use of Artificial Neural Network in Determination of Shade, Light Curing Unit, and Composite Parameters’ Effect on Bottom/Top Vickers Hardness Ratio of Composites." BioMed Research International 2018 (November 12, 2018): 1–9. http://dx.doi.org/10.1155/2018/4856707.
Full textAbstract:
Objective.To assess the influence of light emitting diode (LED) and quartz tungsten halogen (QTH) light curing unit (LCU) on the bottom/top (B/T) Vickers Hardness Number (VHN) ratio of different composites with different shades and determination of the most significant effect on B/T VHN ratio of composites by shade, light curing unit, and composite parameters using artificial neural network.Method.Three composite resin materials [Clearfil Majesty Esthetic (CME), Tetric N Ceram (TNC), and Tetric Evo Ceram (TEC)] in different shades (HO, A2, B2, Bleach L, Bleach M) were used. The composites were polymerized with three different LED LCUs (Elipar S10, Bluephase 20i, Valo) and halogen LCU (Hilux). Vickers hardness measurements were made at a load of 100 g for 10 sec on the top and bottom surfaces and B/T VHN ratio calculated. The data were statistically analyzed with three-way ANOVA and Tukey test at a significance level of 0.05. The obtained measurements and data were then fed to a neural network to establish the correlation between the inputs and outputs.Results.There were no significant differences between the B/T VHN ratio of LCUs for the HO and B shades of CME (p>0.05), but there were significant differences between the B/T VHN ratio of LCUs for shade A2 (p<0.05). No significant difference was determined between the B/T VHN ratio of LCUs for all shades of TNC (p>0.05). For TEC, there was no significant difference between the B/T VHN ratio of halogen and LED LCUs (p>0.05), but a significant difference was determined among the LED LCUs (p<0.05). The artificial neural network results showed that a combination of the curing light and composite parameter had the most significant effect on the B/T VHN ratio of composites. Shade has the lowest effect on the B/T VHN ratio of composites.Conclusion.The B/T VHN ratio values of different resin-based composite materials may vary depending on the light curing device. In addition, the artificial neural network results showed that the LCU and composite parameter had the most significant effect on the B/T VHN ratio of the composites. Shade has the lowest effect on the B/T VHN ratio of composites.
19
Rastelli, Alessandra Nara de Souza, Ricardo Scarparo Navarro, José Roberto Cury Saad, Marcelo Ferrarezi De Andrade, and Vanderlei Salvador Bagnato. "Effect of different light-curing techniques on hardness of a microhybrid dental composite resin." Brazilian Dental Science 17, no. 1 (January 27, 2014): 45. http://dx.doi.org/10.14295/bds.2014.v17i1.950.
Full textAbstract:
<p><strong>Objective</strong>:<strong> </strong>This study assessed the Vickers hardness provided by two LCUs when using (1) direct and indirect light-curing techniques, (2) 40 and 60 seconds and (3) top and bottom surfaces. <strong>Material and Methods</strong>: One halogen Curing Light 2500 (3M Espe) and one LED (MM Optics) were used by direct and indirect (0, 1.0, 2.0 and 3.0 mm of dental structure) techniques during 40 and 60 seconds. The samples were made with Filtek<sup>TM</sup> Z250 in a metallic mould with a central orifice (4 mm in diameter, 2 mm in thickness). The samples were stored in dry mean by ± 24 hours and the hardness measurements were performed in a testing machine (Buehler MMT-3 digital microhardness tester Lake Bluff, Illinois USA). A 50 gf load was used and the indenter with a dwell time of 30 seconds. The data were submitted to multiple ANOVA and Newman-Keuls‘s test (p<0.05). <strong>Results</strong>: Halogen LCU exhibited higher Vickers hardness values than LED mainly because of the power density used. Hardness values were influenced by LCUs, light-curing techniques, irradiation times and surfaces. For both LCUs, hardness values were found to decrease with indirect light-curing technique, mainly for the bottom surface. Samples irradiated for 60 s exhibited higher hardness values when the halogen LCU was used. For 60 seconds, the VHN values were statistically significant greater than 40 seconds. Significant differences in top and bottom surfaces Vickers hardness number (VHN) values were observed among different LCUs used 40 and 60 seconds. <strong>Conclusion</strong>: The LCUs, light-curing techniques, variations of irradiation times, and surfaces (top and bottom) influence the composite hardness. </p><p><strong>Keywords</strong>: Composite resin, LED, Halogen lamp, Hardness, Photo-activation.</p>
20
Hatim, Afra, Widowati Siswomihardjo, and Siti Sunarintyas. "Pengaruh Lama Perendaman dalam Obat Kumur Terhadap Kekerasan Polyethylene Fiber-Reinforced Composites." Jurnal Material Kedokteran Gigi 7, no. 2 (September 1, 2018): 1. http://dx.doi.org/10.32793/jmkg.v7i2.366.
Full textAbstract:
Fiber-reinforced composites (FRC) is a resin base material that strengthen with fiber. In dentistry, these materials interacts with various fluid, such as mouthwash. Mouthwash that contains alcohol affects the physical and mechanical properties of the material. The aim of this research is to determine the effect of immersion duration in mouthwash towards the hardness of polyethylene fiber reinforced composites. The materials used in this research are polyethylene (Fiber UHMWPE, Vactrise), composite resin (MasterFlow, Brazil), and mouthwash (Original Listerine® Antiseptic). Strip-shaped specimens (5x2x2)mm is light cured for 20 seconds. The specimens is divided into K1 (control group), K2 (immersed for 24 hours) and K3 (immersed for 48 hours). Hardness values is measured using Vickers Hardness Test (Buehler, Germany). The data obtained is analyzed using one way anova and followed by LSD test. The results showed the mean of hardness of groups immersed with mouthwash (0, 24, and 48 hours) are 19±0.82 VHN, 14.33±0.25 VHN, and 8.67±0.84 VHN respectively. One way anova test showed there is a significant effect (p<0,05) of immersion duration in mouthwash towards the hardness of polyethylene FRC. LSD test showed significant differences between all groups. The conclusion of this research is prolonged immersion in mouthwashes decreases the hardness of polyethylene FRC.
21
Tauvana, Ade Irvan. "PENGARUH VARIASI TEGANGAN DAN WAKTU PELAPISAN TERHADAP KEKILAPAN, KEKERASAN DAN KEKASARAN PERMUKAAN ALUMINIUM." KURVATEK 1, no. 1 (April 29, 2016): 6. http://dx.doi.org/10.33579/krvtk.v1i1.216.
Full textAbstract:
The objectives of this research are to determine the influence the voltage and time variations of nickel plating against braightness, hardness, and surface roughness of aluminum specimen and to determine the optimum conditions of coating, so that the condition was obtained plating process copper, nickel and chromium are the most effective which can produce the highest brightness and hardness.
Materials Testing square with a length of 5cm, 5cm wide and 0.5 cm thick. Specimen coated copper (12V, during 5 second), then coated with nickel (1V, 2V, 3V, 4V, during 5,10,15,20,25 minutes) variation of voltage and time in the nickel plating is an independent variable of this research, and then coated with chromium (12V during 5 second). Tests conducted to determine surface brightness, hardness and surface roughness.
Brightness test conduct with Luxmeter, hardness test with micro Vickers method with a 10gr load, and surface roughness test with roughness test. Brightness test result shows that specimen (2V,25 minutes) have the highest brightness (78%), and specimen (1V, 5 minutes) have the lowest brigthness(50%). Hardness test results show that the raw material surface have the hardness of is 38.3 VHN, shown at the highest hardness of specimens (2V, 25 minute) = 229 VHN and specimens (3V, 20 minute) = 229 VHN, an increase of 497.9% compared to the basic specimen hardness.
22
Alalkawi, H. J. M., Asifa Mahdi Mohammed, and Raad Hameed Majid. "Influence of Stirring Speed on Mechanical Properties for Cast Nano-Particulate AA7075-Al2O3 Composites." Al-Nahrain Journal for Engineering Sciences 22, no. 2 (July 21, 2019): 109–16. http://dx.doi.org/10.29194/njes.22020109.
Full textAbstract:
Aluminum metal matrix composites are widely employed for improving the mechanical properties. Various fabrication routes like liquid state, solid state and liquid-solid state are currently available for producing these materials. The objective of the present work is the fabrication of nano particulate composites AA7075-Al2O3 with different amount of nano particles (20-30 nm) reinforced material Al2O3 (2, 4 and 6 wt%) using stir casting technique at three stirring speeds (300, 850 and 1500 rpm). Tensile tests of these composites were carried-out to obtain the mechanical properties (ultimate strength and ductility). Vickers hardness tests were also performed to obtain the hardness number (VHN) of these materials. All tests were performed at room temperature. The microstructures of the best mechanical properties’ composites were examined for the three stirring speeds. It was revealed that the ultimate strength (Ϭu) and Vickers hardness (VHN) for the composite containing 6 wt% Al2O3 fabricated at 850 rpm show the best properties compared to the other composites fabricated at 300 and 1500 rpm and the matrix. The Ϭu and VHN were increased by about (36.6 %) and (24.5 %) respectively. Ductility of the strongest composite (6 wt% Al2O3 at 850 rpm speed), however, was the least when compared to other composites and the matrix. With increasing the amount of Al2O3, Ϭu and VHN, an increasing trend was noticed while the ductility shows a reduction trend. The maximum reduction in ductility occurred for the composite containing 6 wt% Al2O3 obtained at 850 rpm. The ductility of the developed composite was reduced by (23 %). The optical microstructures of unreinforced, as-cast Aluminum alloy AA7075 and 6 wt% Al2O3 composites for all stirring speeds show dendrite microstructure resulting from the casting process, but the composite at the stirring speed of 850 rpm shows a more refined microstructure.
23
Puspitasari, Dewi, Maharani Laillyza Apriasari, Dewi Rahayu, and Priyawan Rachmadi. "THE EFFECT OF Musa acuminata AND Ocimum basilicum MIXED EXTRACTS TO THE SURFACE HARDNESS OF BIOACTIVE COMPOSITE RESIN." Dentino : Jurnal Kedokteran Gigi 5, no. 2 (August 15, 2020): 172. http://dx.doi.org/10.20527/dentino.v5i2.8970.
Full textAbstract:
ABSTRACTBackgrounds: The use of mouthwash daily may influence the mechanical properties of bioactive composite resin as a dental restoration, one of the mechanical properties is surface hardness. Herbal mouthwash can be used to minimize the side effect of mouthwash that contain alcohol. Mauli banana stem and basil leaf extracts can be produced into herbal mouthwash. Methods: Thirty specimens (10mm diameter x 2mm thick; n=5/group) bioactive composite resins were immersed in a mixed solution of Mauli banana and basil leaf extracts with concentration of 25%, 50%, 75 %%, 100%, the control group of chlorhexidine gluconate 0.2% and aquadest for 7 days in 37oC. Measurement of the surface hardness was using the Vickers Microhardness Tester with 100 gf load for 15 seconds. Results: One Way ANOVA and Post Hoc Bonferroni exhibited the significant differences (p <0.05) in hardness values between the specimens that immersed in the mixed solution Mauli banana and Basil leaf extracts, which in the concentration of 100% (4,49 ± 4,61 VHN) compared with 25% (38,20 ± 2,58 VHN), 50% (41,40 ± 3,84 VHN) and 75% concentration (40,40 ± 3,55 VHN). There was no siginificant difference (p >0.05) between specimens immersed in CHX, aquadest and the mixed solution of mauli banana and basil leaf extracts in all concentration. Conclusion: There is no change in bioactive composite resin surface hardness after immersed in the mixed solution of Mauli Banana stem (Musa acuminata) and Basil leaf (Ocimum basilicum) extracts.Keywords: Basil leaf extract, Bioactive resin, Mauli Banana stem extract, Surface hardness
24
Badkar, Duradundi Sawant. "Experimental Investigation on Hardness Properties of Laser Hardened Bead Profile of Commercially Pure Titanium Grade3 Using Nd:YAG Laser." Journal of Advanced Manufacturing Systems 17, no. 03 (July 30, 2018): 291–316. http://dx.doi.org/10.1142/s021968671850018x.
Full textAbstract:
This research paper presents the laser transformation hardening (LTH) to improve the surface hardness of commercially pure titanium, nearer to ASTM Grade3 chemical composition of 1.6[Formula: see text]mm thickness sheet using a CW (continuous wave) 2[Formula: see text]kW, with radiation wavelength [Formula: see text][Formula: see text][Formula: see text]m Nd:YAG laser. Full factorial and response surface design approach in Design Expert 9 software have been discussed and evaluated by statistical regression analysis and analysis of variance. The experiment was carried out as the full factorial design (FFD) array of 27 with 3 factors, 3 levels, i.e. 3[Formula: see text] experiments. The selected input parameters are: laser power, scanning speed and focused position, and responses are: Vickers Microhardness on top surface, in fusion zone, and in heat affected zone. FFD and response surface methodology (RSM) were applied to evaluate and optimize the effects of laser process parameters on Vickers microhardness of laser hardened surface. The results show that, the hardness of as-received commercially pure titanium is approximately 153[Formula: see text]VHN and the hardness after laser transformation hardened bead geometrical surface is in the range of 200–240[Formula: see text]VHN. The hardness can be increased with the increase in the scanning speed and decrease in the optimum value of laser power i.e. heat input applied. It has been found that the quadratic model is best fitted for prediction of the Vickers microhardness of laser hardened surface. These findings are significant in modern development of hard surface coatings for corrosion and wear resistant applications. Application of experimental results will be considered in the aerospace, marine, chemical, medicine, automobile and the engineering industries.
25
Purwaningrum, Yustiasih, Triyono, Tegar Rileh Argihono, and Ryan Sutrisno. "Effects of Root Opening on Physical and Mechanical Properties of the Double Side Welded of Ship Materials." Applied Mechanics and Materials 835 (May 2016): 167–72. http://dx.doi.org/10.4028/www.scientific.net/amm.835.167.
Full textAbstract:
The effects of root opening process parameters on the phisical and mechanical properties of mild steel specimens of grade LR Gr A having dimensions 200 mm× 100 mm× 12 mm, welded by gas metal arc welding were investigated. The variation of root opening that used were 3 mm, 5 mm and 7 mm. The physical properties examined with regard with microstructure, macrosructure, and corrosion using optical microscope and stereozoom. The measured of mechanical properties with regard to strength, hardness and toughness using, tensile test, Vickers hardness Test, and Charpy impact test. The test results show the base metal had a hardness of approximately 110 VHN and a maximum hardness of approximately 190 VHN that corellates with microstructure of weld metals. Microstructure of base metal and HAZ are ferite and perlite, while microstructure of weld zone are acicular ferrite and grain boundary ferrite. The corrosion rate of weld metals with various root opening categorized as materials having excellent corrosion resistance value. Welding joints with opening roots 3 mm and 5 mm can be used for construction. All welded specimens exhibited fracture at base metals
26
Djustiana, Nina, Elin Karlina, Arief Cahyanto, Zulia Hasratiningsih, and Rosidah Nurhayati. "Uji Kekerasan Resin Komposit Olahan Sendiri dengan Filler Hidroksiapatit dari Tulang Ikan Air Tawar." Jurnal Material Kedokteran Gigi 7, no. 2 (September 1, 2018): 45. http://dx.doi.org/10.32793/jmkg.v7i2.372.
Full textAbstract:
Resin composite is one of the restoration materials used in dentistry. The study toward resin composite was being done to improve mechanical properties and the biocompatibilities, one of the ways by using hydroxyapatite filler. State of the aim of this study was to evaluate the hardness number of resin composite with hydroxyapatite filler from fresh water fish bones. The study was true experimental using five samples of resin composites processed with hydroxyapatite filler from fresh water fish bones and five samples of fabricated resin composites (GC Solare P) as a control. Hardness was evaluated using the Vickers microhardness testing machine (Leco). The average hardness number of resin composite processed was 18.384 VHN and resin composite made by factory was 27.952 VHN. The results were analyzed statistically by t independent (α=0.05) and showed significantly difference between resin composite processed with hydroxyapatite filler from fresh water fish bones compared to fabricated resin composite. The conclusion from this study showed that the hardness number of resin composite processed with hydroxyapatite filler from fresh water fish bone is lower than fabricated resin composite.
27
Farooq, Imran, Saqib Ali, Intisar Ahmad Siddiqui, Khalifa S. Al-Khalifa, and Mohammed Al-Hariri. "Influence of Thymoquinone Exposure on the Micro-Hardness of Dental Enamel: An In Vitro Study." European Journal of Dentistry 13, no. 03 (July 2019): 318–22. http://dx.doi.org/10.1055/s-0039-1697117.
Full textAbstract:
Abstract Objective The aim of this study was to assess changes in micro-hardness level of enamel after it was exposed to thymoquinone (TQ). Materials and Methods Sixteen enamel blocks were prepared and divided into two groups (each group received eight blocks, n = 8); Gp 1 (control): enamel blocks kept in 100 mL artificial saliva (AS) for 24 hours and Gp 2: enamel blocks kept in a mixture of TQ powder (1 g) and AS (100 mL) for 24 hours. Post-immersion they were subjected to simulated brushing with each sample receiving 8,000 linear strokes. For brushing, 3 mL of AS and TQ oil was used for groups 1 and 2, respectively. Enamel surfaces were analyzed for changes in values of surface micro-hardness (pre-immersion, post-immersion, and post-brushing) by obtaining Vickers hardness number (VHN). Results The present study indicated improvement in micro-hardness levels for both groups although experimental group showed more enhancement. The mean baseline VHN for control group was 498.6, 500.4 for post-immersion, and 503.5 for post-brushing. The mean baseline VHN for experimental group was 448.7, 531 for post-immersion, and 610.3 for post-brushing. Statistically significant differences (p < 0.05) were observed when post-brushing VHN values of both groups were compared and also within the experimental group when post-brushing values were compared with baseline values. Statistical Analysis Wilcoxon signed-rank test was applied for the evaluation of pre- and post-exposure hardness values. Level of significance was ≤0.05. Conclusion The exposure of enamel to TQ led to an improvement in its micro-hardness levels. Further studies are required to understand the mechanism of action of TQ on human tissues.
28
Morales, R., S. Seetharaman, and V. Agarwala. "Mechanical and structural characterization of uniaxially cold-pressed Fe2Mo powders." Journal of Materials Research 17, no. 8 (August 2002): 1954–59. http://dx.doi.org/10.1557/jmr.2002.0289.
Full textAbstract:
In this work, Fe2Mo intermetallic powder, produced by H2 gas reduction of Fe2MoO4 was characterized by techniques like x-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM studies confirmed the presence of nano- and microcrystalline grains of Fe2Mo. The above powders when compressed uniaxially showed a logarithmic relation with “relative density”, δr, of the compacts. The multiple compaction mechanisms were analyzed by Kawakita's and Balshin's models. Vickers hardness number, VHN, was found to increase linearly with δr of the compacts. The hardness of Fe2Mo intermetallic when δr = 1 was estimated as 343 VHN. Using Tabor's analysis, the yield strength of Fe2Mo was found to be about 1100 MPa. This value was further confirmed from the details of relative broadening (112) Bragg peak of Fe2Mo obtained from XRD analyses of Fe2Mo at different compaction pressures.
29
Wisnujati, Andika, and Ahmad Nurhuda. "Analisis Sifat Fisik dan Mekanik Sambungan Las Oxy-Acetylene pada Pelat Baja Karbon Rendah dengan Variabel Nyala Torch Karburasi." Jurnal Engine: Energi, Manufaktur, dan Material 1, no. 2 (November 17, 2017): 1. http://dx.doi.org/10.30588/jeemm.v1i2.253.
Full textAbstract:
<p>Oxy-acetylene welding is widely used in small workshops for car body repair, automobile and motorcycle exhaust, and other improvements using a maximum temperature of 3000oC that can not be done through another process. The purpose of this study was to analyze the effect of torque oxyacetylene flame carburizing on the physical-mechanical properties of low carbon steel plate welding joints. The method employed by using a low carbon steel plate 2 (two) pairs in a butt weld immension of 300 mm x 75 mm x 1 mm. After welding with oxy-acetylene in torch carburizing flame, the specimens were examined through physical observation including microstructure and echanical properties. Micro hardness vickers (VHN) was used to evaluate the harness and tensile properties was determine using the universal testing machine. In the microstructure testing, there is a pearlite and ferrite whose become different dimensions as it is affected by the heat and air pressure of the weld. The result of tensile strength specimen A 174,6 N/mm2 and specimen B 157,65 N/mm2. While the vickers test obtained the highest hardness that is 152.5 VHN in the welding area<em>.</em></p>
30
Handoko, Dwi, and Vivaldi Vivaldi. "Pengaruh Paduan Arang Aktif Kayu Belian/ulin Dan Katalisator Kerang Ale-Ale Pada Proses Pack Carburizing Terhadap Perubahan Komposisi Dan Nilai Kekerasan Baja Karbon Rendah (Low Carbon steel) St 37." Jurnal Vokasi 15, no. 2 (January 21, 2021): 57–64. http://dx.doi.org/10.31573/vokasi.v15i2.159.
Full textAbstract:
To increase the hardness and wear resistance of low carbon steels (low carbon steel), it is usually done by a hardening process, namely by adding carbon elements. One of these processes is by using the Pack carburizing method. In this study, the pack carburizing process will be carried out on low carbon steel St 37 using activated charcoal media from ironwood combined with ale-ale shells catalyst with a composition of 10%, 20%, 30% 40% and 50%. Furthermore, composition testing and hardness testing were carried out using the Vickers method. The results of this study in the composition test, there was an addition of carbon due to diffusion and an increase in the maximum hardness of the catalyst composition by 30% with a hardness of 572.6 VHN.
31
GONDIM, Brenna Louise Cavalcanti, Isabella Cavalcante MEDEIROS, Bruna Palmeira COSTA, Hugo Lemes CARLO, Rogério Lacerda dos SANTOS, and Fabíola Galbiatti de CARVALHO. "Effects of erosive challenge on the morphology and surface properties of luting cements." Revista de Odontologia da UNESP 45, no. 2 (March 15, 2016): 103–9. http://dx.doi.org/10.1590/1807-2577.022315.
Full textAbstract:
Abstract Introduction Few studies investigated the surface properties of luting cements after erosive challenge. Objective To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion Erosive challenge with a cola drink affected the surface properties of all luting cements.
32
de Almeida-Junior, Antonio Alves, Gelson Luis Adabo, Beatriz Regalado Galvão, Diogo Longhini, and Claudinei dos Santos. "Evaluation of Mechanical Properties of Dental Feldsphatic Porcelains for Metal and Zirconia Core." Materials Science Forum 727-728 (August 2012): 1104–7. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1104.
Full textAbstract:
Studies has been reported a significant incidence of chipping of the feldspathic porcelain veneer in zirconia-based restorations. The purpose of this study was to compare the three-point flexural strength (MPa), Weibull parameters, Vickers hardness (VHN) and Vickers indentation fracture toughness (MPa/mm1/2) in feldspatic porcelains for metal and for zirconia frameworks. Bar specimens were made with the porcelains e.MaxCeram (EM) and VitaVM9 (V9) for zirconia core, and Duceragold (DG) and VitaVMK95 (VK) for metal core (n= 15). Kruskal-Wallis and Dun test were used for statistical analysis. There was no significant difference (p=0.31) among the porcelains in the flexural strength (Median= 73.2; 74.6; 74.5; 74.4). Weibull calculation presented highest reliability for VK (10.8) followed by EM (7.1), V9 (5.7) and DG (5.6). Vickers hardness test showed that EM (536.3), V9 (579.9) and VK (522.1) had no difference and DG (489.6) had the lowest value (p.001). The highest fracture toughness was to VK (1.77), DG (1.58) had an intermediate value while V9 (1.33) and EM (1.18) had the lowest values (p.001). Despite of the suitable flexural strength, reliability and high hardness, the porcelains used to zirconia-based fixed dental prostheses showed lower fracture toughness values.
33
Subarmono, Subarmono, Jamasri Jamasri, M. W. Wildan, and Kusnanto Kusnanto. "Mechanical Properties of Aluminum/fly Ash Composites Produced by Hot Extrusion." Material Science Research India 7, no. 1 (June 25, 2010): 95–100. http://dx.doi.org/10.13005/msri/070110.
Full textAbstract:
This research aims to investigate mechanical properties of aluminum matrix composites reinforced with fly ash (AMC/Fly ash) produced using hot extrusion.AMC/Fly ash was prepared from aluminum fine powder as matrix and fly ash as reinforcement. The various amount of fly ash of 5%; 7.5%; 10%; 12.5% and 15% wt were added to the aluminum fine powder. Each composition was mixed using rotary mixer for 3 hours. The mixture was compacted using uniaxial pressing with a pressure of 100 MPa to produce green body. The green body was hot extruded with an extrusion ratio of 0.25 and temperature of 600ºC. Bending strength, Vickers hardness, wear rate and porosity of the AMC/fly ash were measured. The microstructure was observed using SEM. The results show that mechanical properties of the composites such as bending strength and Vickers hardness increase, porosity and wear rate decrease with increasing fly ash content up to 12.5 wt %. Above 12.5 wt % of fly ash those mechanical properties of composites seems to be inverse. The properties of AMC/12.5 wt % fly ash produced using hot extrusion from green body showing the best properties in term of the bending strength, Vickers hardness, porosity and wear resistance, that are 302 MPa; 79 VHN; 0.73 % and 0,0095 mg/(MPa.m), respectively.
34
Bahrani, Farideh, Mahroo Vojdani, Anahita Safari, and Ghasem Karampoor. "Comparison of Hardness and Surface Roughness of Two Denture bases Polymerized by Different Methods." World Journal of Dentistry 3, no. 2 (2012): 171–75. http://dx.doi.org/10.5005/jp-journals-10015-1151.
Full textAbstract:
ABSTRACT Purpose The aim of this study was to evaluate mechanical property hardness and surface roughness (Ra) of different polymerization acrylic resins used for denture bases. Materials and methods A total of 30 specimens were prepared and divided in two groups. A total of 15 samples were processed by the compression molding technique using Meliodent (heatcured). Another 15 samples were processed with cold-cured resin Futura Gen via the injection molding technique. Hardness testing was conducted using a Vickers hardness tester. The Ra test was performed by a profilometer. Data were analyzed using the independent sample t-test and differences were statistically significant at the 0.05 level. Results The Vickers hardness numbers (VHN) were 20.8 ± 2.39 for Meliodent and 21.18 ± 1.42 for FuturaGen, which was not significantly different (p > 0.05). The Ra of Meliodent was 0.92 ± 0.23 µm and for FuturaGen it was 0.84 ± 0.37 µm. There were no significant changes in roughness. Conclusion The hardness and Ra of Meliodent and FuturaGen were not significantly different. Therefore, we recommend the use of FuturaGen for manufacturing denture base materials. How to cite this article Bahrani F, Safari A, Vojdani M, Karampoor G. Comparison of Hardness and Surface Roughness of Two Denture bases Polymerized by Different Methods. World J Dent 2012;3(2):171-175.
35
Flury, S., A. Peutzfeldt, and A. Lussi. "Influence of Surface Roughness on Mechanical Properties of Two Computer-aided Design/Computer-aided Manufacturing (CAD/CAM) Ceramic Materials." Operative Dentistry 37, no. 6 (October 1, 2012): 617–24. http://dx.doi.org/10.2341/11-391-l.
Full textAbstract:
SUMMARY The aim of this study was to evaluate the influence of surface roughness on surface hardness (Vickers; VHN), elastic modulus (EM), and flexural strength (FLS) of two computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials. One hundred sixty-two samples of VITABLOCS Mark II (VMII) and 162 samples of IPS Empress CAD (IPS) were ground according to six standardized protocols producing decreasing surface roughnesses (n=27/group): grinding with 1) silicon carbide (SiC) paper #80, 2) SiC paper #120, 3) SiC paper #220, 4) SiC paper #320, 5) SiC paper #500, and 6) SiC paper #1000. Surface roughness (Ra/Rz) was measured with a surface roughness meter, VHN and EM with a hardness indentation device, and FLS with a three-point bending test. To test for a correlation between surface roughness (Ra/Rz) and VHN, EM, or FLS, Spearman rank correlation coefficients were calculated. The decrease in surface roughness led to an increase in VHN from (VMII/IPS; medians) 263.7/256.5 VHN to 646.8/601.5 VHN, an increase in EM from 45.4/41.0 GPa to 66.8/58.4 GPa, and an increase in FLS from 49.5/44.3 MPa to 73.0/97.2 MPa. For both ceramic materials, Spearman rank correlation coefficients showed a strong negative correlation between surface roughness (Ra/Rz) and VHN or EM and a moderate negative correlation between Ra/Rz and FLS. In conclusion, a decrease in surface roughness generally improved the mechanical properties of the CAD/CAM ceramic materials tested. However, FLS was less influenced by surface roughness than expected.
36
Pelsue, Brian M., Spiros Zinelis, T. Gerard Bradley, David W. Berzins, Theodore Eliades, and George Eliades. "Structure, Composition, and Mechanical Properties of Australian Orthodontic Wires." Angle Orthodontist 79, no. 1 (January 1, 2009): 97–101. http://dx.doi.org/10.2319/022408-110.1.
Full textAbstract:
Abstract Objective: To investigate the surface morphology, structure, elemental composition, and key mechanical properties of various sizes and tempers of Australian wires. Materials and Methods: Three types of Australian wire were used: 0.016″ regular, 0.018″ regular+, and 0.018″ special+ (A.J. Wilcock, Whittlesea, Victoria, Australia). Each type of wire was subjected to scanning electron microscopy (SEM) analysis, x-ray energy dispersive spectroscopy (EDS) investigation, Vickers hardness testing, and tensile testing. The modulus of elasticity and ultimate tensile strength were determined. Hardness, modulus, and strength data were analyzed with one-way analysis of variance (ANOVA) and Tukey testing at the .05 level of significance. Results: All three types of Australian wire were found to possess considerably rough surfaces with striations, irregularities, and excessive porosity. All three wire types had high levels of carbon and a similar hardness, which ranged within 600 VHN (Vickers hardness number), and a similar modulus of elasticity (173 to 177 GPa). The 0.018″ special+ had a significantly lower tensile strength (1632 MPa) than the 0.016″ regular and the 0.018″ regular+ wire (2100 MPa). Conclusions: Australian wires did not show variation implied by the size or temper of the wires.
37
Sajjan, Sudheer S., Mithun V. Kulkarni, S. Ramesh, P. C. Sharath, Rajole Sangamesh, Aravind Kumar, and Rangappa Rajesh. "Evaluation of Microstructure and Mechanical Properties of Multi Axial Forged LM2 Aluminum Alloy." Materials Science Forum 969 (August 2019): 297–302. http://dx.doi.org/10.4028/www.scientific.net/msf.969.297.
Full textAbstract:
Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture.
38
Sundriyal, S., Vipin, and RS Walia. "Experimental investigation and performance enhancements characteristics of gaseous assisted powder mixed near dry electric discharge machining." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 235, no. 4 (January 18, 2021): 1048–58. http://dx.doi.org/10.1177/0954408920988424.
Full textAbstract:
Gaseous assisted powder mixed near dry EDM (GAPMND-EDM) is one of the recent hybrid technologies, which not only enhance the machining performance, but at the same time, high quality products with better surface quality characteristics can also be achieved. In this study, the response parameters were material removal rate, surface finish, micro hardness and residual stress. It was found that the maximum material removal rate (MRR 3.379 mg/min) was achieved with combination of (dielectric) oxygen gas with graphite powder while lowest surface roughness (SR 1.11 μm) was found to be with dielectric argon gas with graphite additives. Highest micro hardness (MH) and lowest residual stress (RS) was 820.30 Vickers hardness number (VHN) and 229 MPa found with dielectric combination of zinc additives with argon gas.
39
Yuristiawan, Farid, Gunawan Gunawan, and Detty Iryani. "PERBANDINGAN KEKERASAN BAHAN GLASS IONOMER CEMENT YANG DIRENDAM ANTARA OBAT KUMUR BERALKOHOL DENGAN OBAT KUMUR BEBAS ALKOHOL." Andalas Dental Journal 4, no. 2 (December 3, 2016): 98–105. http://dx.doi.org/10.25077/adj.v4i2.59.
Full textAbstract:
Glass ionomer cement is one of the filling material that often used on the field of dentistry because it is relatively less expensive and mostly available. It’s existence in the mouth makes it susceptible to any substance that comes into mouth one of them is mouthwash which is a solution that used for many purposes such as antiseptic, astrigent, to prevent caries and bad breath. The aim of this research is to know the comparison of surface hardness of glass ionomer cement which soaked in alcohol containing mouthwash and alcohol-free mouthwash. This research is a laboratoric experimental type study. Sampels made from GC FUJI IX GP EXTRA for as much as 30 sampels were made and then soaked in artificial saliva for the first 24 hours inside incubator which temperature and humidity were controlled. Sampels then divided into 3 groups. First group will be soaked in alcohol containing mouthwash, second group will be soaked alcohol-free mouthwash and control group will be soaked in artificial saliva for 6 hours inside incubator. Listerine is the mouthwash that was used on this research and surface hardness was examined using Vickers Hardness Tester. The result of this research shows mean value for surface hardness of the first group is 16.36 VHN, 24.04 VHN for second group, and 43.60 VHN for control group. The result one way ANOVA with post hoc Bonferroni comparing test show significant results p = 0.00. In Conclusion there are significant differences of surface hardness between each groups, which surface hardness of the first group is lower than the second group, and both surface hardness of the first and second group are lowered than control group (p = 0.00).
Key words : Glass Ionomer Cement, Mouthwash, Surface Hardness
40
Silva Costa, Simone Xavier, Anne Buss Becker, Alessandra Nara de Souza Rastelli, Leonor de Castro Monteiro Loffredo, Marcelo Ferrarezi de Andrade, and Vanderlei Salvador Bagnato. "Effect of Four Bleaching Regimens on Color Changes and Microhardness of Dental Nanofilled Composite." International Journal of Dentistry 2009 (2009): 1–7. http://dx.doi.org/10.1155/2009/313845.
Full textAbstract:
Objective. The purpose of this study was to compare the color changes and microhardness of a nanocomposite after four bleaching regimens.Materials. Twenty-five specimens(n=25)were made with a nanocomposite resin (Filtek Supreme XT). The specimens were divided into five groups equally(n=5): bleaching groups and control group, as follows: G1: artificial saliva at37∘C; (control) G2: hydrogen peroxide (HP) at 7%; G3: hydrogen peroxide (HP) at 35%; G4: carbamide peroxide (CP) at 10%; G5: carbamide peroxide (CP) 35%. Color measurements were made with spectrophotometer using CIELAB color scale. The Vickers hardness (VHN) measurements were performed at the top surface. The data were analyzed with two-way Analysis of Variance.Results.ΔE and VHN mean values into the groups were not statistically different, however, the VHN mean values before and after storage and bleaching showed statistically significant differences.Conclusion. Nanocomposite samples showed no significant alteration (color and microhardness) after bleaching. Thus, no replacement of restorations is required after bleaching.
41
da Cruz, Fernanda Zander Grande, Christiana Zander Grande, Douglas Augusto Roderjan, César Augusto Galvão Arrais, Adriana Postiglione Bührer Samra, and Abraham Lincoln Calixto. "Effect of etch-and-rinse and self-etching adhesive systems on hardness uniformity of resin cements after glass fiber post cementation." European Journal of Dentistry 06, no. 03 (July 2012): 248–54. http://dx.doi.org/10.1055/s-0039-1698958.
Full textAbstract:
ABSTRACTObjectives: To evaluate the effects of etch-and-rinse and self-etching adhesive systems on Vickers hardness (VHN) uniformity of dual-cured resin cements after fiber post cementation.Methods: Fifty glass fiber posts were cemented into bovine roots using the following cementing systems: Prime&Bond 2.1 Dual Cure and Enforce with light-activation (PBDC-LCEN); Prime&Bond 2.1 and Enforce with light-activation (PB-CLEN); Prime&Bond 2.1 Dual Cure and Enforce without light exposure (PBDC-SCEN); ED Primer and Panavia 21 (ED-SCPN); and Clearfil SE Bond and Panavia 21 (CF-SCPN). The roots were stored in distilled water for 72 h and transversely sectioned into thirds (coronal, medium, and apical). The VHN values of the resin cement layers were measured close to the post and to the dentin wall on the transversely sectioned flat surfaces. The results were analyzed by three-way repeated measures analysis of variance (ANOVA) and Tukey’s post-hoc test (pre-set alpha of 5%).Results: Most resin cements presented higher VHN values near the post than near the dentin wall. The ED-SCPN group showed the highest VHN values regardless of the root third, while the selfcured group PBDC-SCEN exhibited the lowest values. The resin cements from the light-activated groups PBDC-LCEN and PB-LCEN showed lower VHN values at the apical third than at the coronal third. The VHN values were not influenced by the root third in self-cured groups PBDC-SCEN, EDSCPN, and ED-SCPN.Conclusions: Depending on the product, bonding agents might promote changes in hardness uniformity of resin cements after post cementation. (Eur J Dent 2012;6:248-254)
42
Daryono, Daryono, Topan Prihantoro, and Ady Setiawan. "Pengaruh Kuat Arus Las Terhadap Sifat Mekanis dan Struktur Mikro Sambungan Las Besi Tuang Kelabu menggunakan Elektroda Nikel dengan Proses Pengelasan SMAW." Accurate: Journal of Mechanical Engineering and Science 2, no. 1 (April 29, 2021): 1–6. http://dx.doi.org/10.35970/accurate.v2i1.585.
Full textAbstract:
This study aims to determine the effect of welding current on the mechanical properties and microstructure of graycast iron welding joints using nickel electrodes with the SMAW welding process. The research method used wasexperimental study, starting with preparing the workpiece, welding process, making test specimens and testing the weldspecimens. The material to be joined is gray cast iron metal with a butt joint of a 60 ° open seam V open angle. The weldingprocess used uses SMAW with a current of 80 Amperes, 85 Amperes and 90 Amperes. The added material used was anENiFe-Cl type CIN 2 electrode with a diameter of 2.6 mm. Hardness testing was carried out using the Vickers method andmicrostructure testing using an optical microscope. The results showed that the maximum hardness value of the parentmetal occurred at the welding current strength of 85 Amperes, which was 192.17 VHN, then the maximum hardness value ofthe HAZ area occurred at the welding current strength of 85 Amperes, which was 203.46 VHN, while the maximumhardness value of the weld metal was 203.46 VHN. metal) occurred at a welding current of 90 Amperes, which was 211.18VHN. The results of the microstructure observation showed that the matrix formed on the parent metal was pearlite withgraphite in the form of flakes. The micro structure formed in the HAZ area was a martensite structure. Meanwhile, themicrostructure of weld metal consists of an austenite matrix with an even distribution of graphite particles.
43
Ikhsan, Nurul, Nila Kasuma, and Didin Kustantiningtyastuti. "PERBEDAAN KEKERASAN PERMUKAAN BAHAN RESTORASI RESIN KOMPOSIT NANOFILLER YANG DIRENDAM DALAM MINUMAN RINGAN BERKARBONASI DAN MINUMAN BERALKOHOL." Andalas Dental Journal 4, no. 1 (June 14, 2016): 55–66. http://dx.doi.org/10.25077/adj.v4i1.49.
Full textAbstract:
Resin composite is dental material filling that is commonly used in dentistry which has good physical properties, mechanical and aesthetics. The properties that have an important role in the resistance of the composite resin surface hardness which directly involved when contact with food, drink and salivary. The purpose of this research is to evaluate the effect of carbonated soft drink and alcoholic beverages on the surface hardness of nanofiller composite resin.The method used in this research is post test only control group design. Samples were made using the mold made of stainless steel, with diameter of 6mm and tick of 2mm, composite was manipulated according to the manufacture’s instructions, and then immersed in aquades, carbonated soft drink and alcoholic beverages for 18 hours in a temperature of 37ºC. Samples were tested using Vickers Hardness Test. Data analysis using Kruskal-Walis test.The result show that the nanofiller composite resin which immersed in alcoholic beverages has higher surface (81,04±10,44 VHN), whreas the composite which immersed in aquades and carbonated soft drink has the surface hardness (70,20±16,6 dan71,10±15,96 VHN). The result of data analysis showed that the data are not distributed normally and showed a significant value of p>0,05. From this research can be concluded that there is no significant differences in surface hardness of nanofiller composite resin which immersed in carbonated soft drink and alcoholic beverages.
Keywords: Resin Komposit, nanofiller, surface hardness, mechanical properties.
44
Winardi, Yoyok. "Effect of Heat Treatment on Physical and Mechanical Properties of Cemented Carbide and Carbon Steel Brazed Joints." R.E.M. (Rekayasa Energi Manufaktur) Jurnal 4, no. 2 (December 30, 2019): 169–75. http://dx.doi.org/10.21070/r.e.m.v4i2.812.
Full textAbstract:
Cemented carbides are joined with steel to be used as a cutting tool. Brazing is one of a method joinning metals that has the potential to combine different types of materials such as cemented carbide and steel. This study aimed to investigate the effect of heat treatment on the microstructure and the distribution of the hardness value brazed joint between cemented carbide and carbon steel. The heat treatment was carried out at a temperature of 700oC, 725oC, and 750oC for 30 minutes. The joint area is observed using SEM equipped with EDS. The distribution of hardness value was tested using a micro vickers testing machine. Microstructure observations and SEM-EDS analysis show that the junction region consists of 3 parts, part I is the phase of Cu solution enriched solid, part II phase of the solid solution with the highest percentage of Ag, and part III is the eutectic phase of Ag-Cu-Zn . EDS test results in each section show that the value of element C increases when the treatment temperature is increased. The hardness test results show that the distribution of the hardness value increases when the treatment temperature is added. The hardness of the test specimen without treatment reached 112.73 VHN. The highest hardness value is 131.88 VHN at 750oC. Thus the heat treatment affects the microstructure and the rate of diffusion of metal elements. The higher the temperature, the diffusion rate of the metal element increases, so that it affects mechanical.
45
Karlina, Elin, Kosterman Usri, Renny Febrida, Camellia Panatarani, I. Made Joni, and Yunita Fatmala. "Mechanical Test of Aluminum-Zirconium-Silicate Composite Prototype with Filler Volume Variation." Key Engineering Materials 829 (December 2019): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.829.81.
Full textAbstract:
Recently, ceramic material has become a main object of scientific interest especially in dental material. The advance of dental materials technology has led to use of zirconia-based ceramics for composite filler. In this study, composite filler has been synthesized from natural zircon sand through geopolymerization method. Composite prototype were made with different filler volume to evaluate mechanical properties including hardness number and diametral tensile strength. Samples divided into two groups with 50 wt% filler volume (group A) and 75 wt% filler volume (group B) which 3 samples for each group. The surface micro hardness of each group tested by Leco M-400-H1 vickers microhardness testing machine and for diametral tensile strength tested using universal testing machine (Lloyd) with crosshead speed of 1,0 ± 0,25 mm/min. The data were analyzed using independent sample t-test. The results showed that the average of hardness number on group A was 13,8 VHN while for group B was 24,1 VHN. The average of diametral tensile strength for group A was 20,461 MPa and 27,689 MPa for group B. Statistical result showed that the value (P<0,05). The conclusion, there is a signifficant difference on the result of hardness test between group A (50 wt% filler volume) and group B (75 wt% filler volume) and also on diametral tensile strength test.
46
BISWAS, A., U. K. CHATTERJEE, LIN LI, I. MANNA, and J. DUTTA MAJUMDAR. "LASER ASSISTED SURFACE MODIFICATION OF Ti–6Al–4V FOR BIOIMPLANT APPLICATION." Surface Review and Letters 14, no. 04 (August 2007): 531–34. http://dx.doi.org/10.1142/s0218625x07009700.
Full textAbstract:
The present study aims at enhancing the wear resistance of Ti –6 Al –4 V by laser surface nitriding. Laser surface treatment has been carried out by melting of the sand blasted Ti –6 Al –4 V substrate using a high power continuous wave Diode laser with nitrogen as shrouding environment (at a gas flow rate of 51/min). Laser surface nitriding led to formation of dendrites of titanium nitrides. The microhardness is improved to a maximum of 900–950 VHN (Vickers hardness number) in laser surface nitriding as compared to 260 VHN of the as-received substrate. Surface nitriding increased primary potential for pit formation (Epp1) as compared to Ti –6 Al –4 V . Biocompatibility behavior showed a better cell viability due to surface nitriding as compared to the as-received Ti –6 Al –4 V .
47
Ahmadi, Haerul, Rizky Abdul Aziz, Suprapto Suprapto, Tjipto Sujitno, and Sophie Hapsari. "Study of Microstructural and Corrosion Properties of Aluminium Alloy 7075 after Plasma Nitriding." Jurnal Sains Materi Indonesia 21, no. 1 (May 1, 2020): 1. http://dx.doi.org/10.17146/jsmi.2019.21.1.5649.
Full textAbstract:
Plasma nitriding is a treatment process of metals by depositing nitrogen into metal that considered to be nitrided by mean of increasing the mechanical, physical, and chemical properties of the metal. This treatment will form a hard layer compund of Al-N on the surface of the sample. In this study, aluminium alloy 7075 was nitrided which the application of it to structural part of aircraft makes it vulnarable to not only corrosion and wear attack but also decreasing the hardness of the material. One method to overcome these issues is plasma nitriding. The purpose of of this research is to do the characterizations of plasma nitrided aluminium alloy 7075 regarding its microstructure, mechanical, and chemical properties. The characterizations that had been done were microhardness Vickers testing, SEM-EDX, and electrochemical corrosion testing Potensiostat. The hardness of the sample increased 55% from 75,88 VHN (raw material) to 117,68 VHN (at optimum parameter). The depth of the white layer of plasma nitriding is approximately 6 µm, while the EDX result reported carbon, oxygen, and nitrogen presence. Corrosion testing showed that the highest corrosion rate is on the raw material, 0,15393 mpy. While the optimum one is 0,07184 mpy.
48
Moqbel, Nawal M., Majed Al-Akhali, Sebastian Wille, and Matthias Kern. "Influence of Aging on Biaxial Flexural Strength and Hardness of Translucent 3Y-TZP." Materials 13, no. 1 (December 19, 2019): 27. http://dx.doi.org/10.3390/ma13010027.
Full textAbstract:
The purpose of this research was to evaluate the influence of aging and surface treatment on surface roughness, biaxial flexural strength (BFS), and Vickers hardness (VHN) of translucent dental zirconia. Half of 80 disc-shaped zirconia specimens (1.2 mm thickness and 12 mm diameter) were aged (group A) in an autoclave for 20 h (134 °C and 0.2 MPa) and the other half were not aged (group N). Specimens were subjected to: no surface treatment (SIN), particle air-abrasion with 50 µm alumina particles at 1 bar (0.1 MPa) and 2.5 bar (0.25 MPa), or polishing down to 1 µm (POL). Specimens were analyzed using X-ray diffraction, laser scanning microscope, BFS, and VHN tests. Three groups (N-SIN, N-POL, and A-POL) showed almost no monoclinic phase. While other groups showed monoclinic phase ratios ranging from 7.5 vol. % ± 2.4 vol. % (N-0.1 MPa) to 41.5 vol. % ± 0.3 vol. % (A-0.1 MPa). Aging and particle air-abrasion increased significantly the BFS, ranging from 720 ± 37 MPa (N-SIN) to 1153 ± 92 MPa (N-0.1 MPa). The hardness was not influenced significantly by aging. A certain amount of monoclinic phase at the surface strengthens the high translucent dental zirconia, while hardness and roughness are not influenced. The pressure of particle air-abrasion showed no influence on the evaluated properties.
49
Darmawan, Agung Setyo, Suprapto, Tjipto Sujitno, Dicky Efendi Surya Putra, and Ridhwan Rafi Pangestu. "Increased Hardness and Wear Resistance of Commercially Pure Titanium by a Plasma Nitrocarburizing." Materials Science Forum 1029 (May 2021): 33–40. http://dx.doi.org/10.4028/www.scientific.net/msf.1029.33.
Full textAbstract:
The tribological properties of commercially pure titanium need to be improved when applied as a friction component. This research investigated the effect of plasma nitrocarburizing process on the hardness and wear resistance of commercially pure titanium. The plasma nitrocarburizing process was carried out with a ratio of the composition of N2 gas and CH4 gas of 1:1, 1:2 and 1:3. Metallographic test by scanning electron microscopy was carried out to observe phase modifications on the surface of the material. Compounds formed in a thin layer on the surface of the commercially pure titanium were observed by X-Ray Diffraction testing. Furthermore, Vickers hardness and wear testing were carried out to determine the effect of the plasma nitrocarburizing process. The results showed an increase in hardness and wear resistance. The surface hardness of the untreated commercially pure titanium was 105.75 VHN and increased to 156.76, 211.12 and 236.32 VHN after the plasma nitrocarburizing process was carried out with a ratio of N2 gas and CH4 gas composition of 1:1, 1:2 and 1:3, respectively. The reduction in specific wear rate was experienced by commercially pure titanium. The specific wear rate of the untreated commercially pure titanium was 4.468E-8 mm2/kg. The plasma nitrocarburizing process, which was carried out with a ratio of N2 gas and CH4 gas composition of 1:1, 1:2 and 1:3, reduced the specific wear rate to 2.812E-8, 1.176E-8 and 6.14E-9 mm2/kg, respectively.
50
Takarini, Veni, Sianny Surya Putri Kurnia, Dede Taufik, Arief Cahyanto, and Zulia Hasratiningsih. "Surface Characterization of Dental Porcelain Made from Sumatera Natural Sand." Key Engineering Materials 782 (October 2018): 238–43. http://dx.doi.org/10.4028/www.scientific.net/kem.782.238.
Full textAbstract:
This research reported hardness and porosity morphology results on five different sintering temperatures as surface characterization of dental porcelain made from Sumateran natural sand mixture composition to prevent excessive wear. Porosity morphology was characterized with JEOL Scanning Electron Microscope (SEM), while the average hardness of each 5 different indented areas was performed with 1000 gr load for 15 seconds using Zwick Roell Vickers Hardness Tester. The result of this study shows that the higher sintering temperature correlates to higher hardness number. SEM analysis indicate less porosity appear in the samples sintered in higher temperature. By modifying the mixture, this study has significantly lowered the hardness number results compared to our previous research samples yielded 936,06 VHN. It can be concluded that positive correlation between higher temperature and hardness emerged from the surface characterization results of the dental porcelain made from Sumatera natural sand. In contrasts the porosity appear to be less developed in higher temperature. However, cracks and pores followed the indentation as in common ceramic products. Further improvement is needed with finding the optimum temperature of desired hardness number and predictable porosity, which resemble tooth enamel.