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Journal articles on the topic 'Microstructure; Hardness'

Author: Grafiati

Published: 5 June 2025

Last updated: 15 July 2025

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Suherman, Suherman, Susri Mizhar, Andi Putra, Sutiman Sutiman, and Zainal Arifin. "Analisa Komparasi Sifat Fisis dan Mekanis Piston Sepeda Motor dari Empat Pabrikan." Jurnal Pendidikan Vokasi Otomotif 6, no. 2 (2024): 107–14. http://dx.doi.org/10.21831/jpvo.v6i2.72932.

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The piston is an essential component in the internal combustion system. Unfortunately, most piston products on the market are of low quality, which is detrimental to consumers. Most pistons sold in spare parts shops in Medan City have varying prices and different quality. The study compares four manufacturers' chemical composition, microstructure and hardness of the pistons of 4-stroke motorcycles. The four types of pistons were purchased at an automotive component sales shop in Medan city. The pistons were cut by machine and then analyzed for chemical composition, microstructure and hardness. The research results show that the chemical composition of the four-piston manufacturers is almost similar, where the silicon content ranges from 2-3%, which is a hypoeutectic Al-Si aluminium alloy. Interestingly, the hardness values and microstructure of pistons are different. The hardness value for brand X is the highest compared to other products, at 41.16 VHN. Microstructural observations show that the microstructures of manufacturers W, X and Y are similar, where the Si particles are evenly distributed with almost uniform sizes. Meanwhile, the Z manufacturer shows a microstructure with fibrous Si particles with a coarse SDAS size.

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Zheng, Hua, Kai Ming Wu, S. F. Sun, and G. W. Hu. "Niobium-Alloyed Steel Treated by Quenching-Partitioning-Tempering." Applied Mechanics and Materials 528 (February 2014): 149–52. http://dx.doi.org/10.4028/www.scientific.net/amm.528.149.

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Given the strong recent interest in quenching-partitioning-tempering processed steels, the Niobium-alloyed medium carbon steel was investigated here. The microstructural observations and hardness were analyzed by optical microscope, transmission electron microscope, X-ray diffraction and hardness test. Results show that when quenched at 210°C and partitioned at 450°C, the quenching partitioning-tempering process leads to ultra fine-grained microstructures of martensite, retained austenite and carbides. And the microstructure and hardness changed differently with the increase of partitioned time.

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CHEN, YINGCHUN, and KAZUHIRO NAKATA. "FRICTION STIR PROCESSING OF SKD61 TOOL STEEL." International Journal of Modern Physics B 23, no. 06n07 (2009): 1116–21. http://dx.doi.org/10.1142/s0217979209060555.

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In this study, SKD61 tool steel was friction stir processed (FSP) using a polycrystalline cubic boron nitride (PCBN) tool. Microstructure evolution and mechanical property in FSP zone were investigated. Microstructural observation results showed that the microstructures in FSP zone surface were fine grains in the range of 1 - 4 μm due to large plastic deformation during FSP. Micro-hardness test results showed that the average hardness value in FSP zone was 773 HV, 3.7 times the hardness in base metal (210 HV). The wear test results showed that FSP surface showed a significantly lower wear rate than that of the base material at all loads. The relation between microstructural evolution and mechanical property in FSP zone was discussed.

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Mrwata, Khutso, Charles Siyasiya та Nana Arthur. "Microstructural characterization of additively manufactured Ti-6Al-4V with the addition of β-stabilizer, niobium". MATEC Web of Conferences 388 (2023): 08006. http://dx.doi.org/10.1051/matecconf/202338808006.

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This study investigated the influence of beta stabilizer niobium on the microstructure and hardness of Ti-6Al-4V. The relationship between increased the concentration of alloying elements into Ti-6Al-4V is generally associated with an increase in hardness due to solid solution strengthening. The research involved the fabrication of a series of laser engineering net shaping (LENS™) Ti-6Al-4V alloys with varying concentrations of niobium (13%, 20%, and 28%) to determine whether increasing the Nb content has an influence on the concentration of Nb dissolved into Ti-6Al-4V. The microstructures of these alloys were analysed the hardness examined. the results revealed that the solid solution strengthening did not lead to a proportional increase in hardness as expected. Further microstructural examination showed that the alloy with 13% Nb exhibited a distinct microstructure with a higher concentration of un-melted Nb particles, whereas the alloy with 28% Nb had a higher dissolution of Nb into the Ti-6Al-4V. The least percentage of Nb dissolved into the Ti-6Al-4V compared to the addition of 28% Nb. Increased Nb content resulted in a higher percentage of Nb dissolved in Ti-6Al-4V but the lower hardness value. The undissolved Nb did not contribute solid solution strengthening but rather the presence of defects, and features of microstructure are responsible for hindering the ease of plastic deformation.

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Emmanuel. O. Onche, A.P. Ihom, Emmanuel Udama Odeh, and Aondona T. Philip. "Microstructural analysis of some reinforcement steel rods used for concrete reinforcement and their effect on the mechanical properties, and carbon equivalent values of the reinforcement steel rods." Global Journal of Engineering and Technology Advances 15, no. 2 (2023): 116–23. http://dx.doi.org/10.30574/gjeta.2023.15.2.0080.

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The microstructural analysis of some reinforcement steel rods used for concrete reinforcement and their effect on the mechanical properties, and carbon equivalent values of the reinforcement steel rods have been studied. The work subjected the samples to test specimen preparation as required by standard specification for each test. Samples from five different mini mills were investigated for hardness, impact strength, composition, and microstructure. The result obtain from the work, has clearly shown that the microstructure of all the samples investigated reflected the hardness, impact strength, and the CEV of the samples. The microstructure of sample D with spheroidal pearlite dark areas, and a ferrite matrix had the highest hardness value of 34.61BHN, impact strength of 274.7J and CEV of 0.545. These values correlate with the microstructure. The work showed that as the CEV is increased the hardness and the impact strength of the material also increased. The work also show that as the total carbon (TC) % in the samples increased the microstructure becomes darker and the hardness and the impact strength also increased. In conclusion the microstructure of the reinforcement steel rods had effect on the hardness, impact strength properties, and carbon equivalent value of the reinforcement steel rods.

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Emmanuel., O. Onche, Ihom A.P., Udama Odeh Emmanuel, and T. Philip Aondona. "Microstructural analysis of some reinforcement steel rods used for concrete reinforcement and their effect on the mechanical properties, and carbon equivalent values of the reinforcement steel rods." Global Journal of Engineering and Technology Advances 15, no. 2 (2023): 116–23. https://doi.org/10.5281/zenodo.8046817.

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Kožuh, Stjepan, Mirko Gojić, Ivana Ivanić, Aleš Nagode, and Kristijan Jerković. "Welding of pipes from low-carbon steel by TIG procedure." Zavarivanje i zavarene konstrukcije 68, no. 4 (2023): 133–36. http://dx.doi.org/10.5937/zzk2303133k.

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In this work the results of welding the pipes from low-carbon steel St 35.8 (Č.1214, DIN17175, W.Nr. 1.0305, EN-P235GH) by TIG procedure were shown. After welding, the microstructure analysis by means of optical microscope was performed. Microstructural analysis out on the base material, heat affected zone and melting zone was carried. It was found that the base material has ferrite-pearlite microstructure with hardness 148 HV10, while in the heat affected zone is present ferrite-pearlite microstructure with Widmanstatten ferrite in some places with hardness 176 HV10. A cast microstructure consisting of ferrite and bainite was observed in the melting zone with hardness 228.7 HV10.

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Zhang, Xiaodan, Niels Leergaard Pedersen, Peder Klit, and Dorte Juul Jensen. "Heterogeneous microstructure and failure analysis of yaw gear rings." IOP Conference Series: Materials Science and Engineering 1249, no. 1 (2022): 012055. http://dx.doi.org/10.1088/1757-899x/1249/1/012055.

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Abstract The microstructure and hardness of two cracked and failed steel (42CrMo4) teeth from two different yaw rings have been investigated. It is shown that the surface quenching and tempering treatments introduce heterogeneous microstructures with a low-temperature tempered hard martensite surface layer and a high-temperature tempered matrix. This is common to both teeth, however, the gradient microstructure and hardness are different for these two yaw rings. It is suggested that this difference in gradient strongly affects cracking and failure. The failure mechanisms for the two teeth are discussed based on the microstructure and hardness analysis.

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Wang, Gui Cheng, Bin Jiao, Jun Feng Zou, and Hong Jie Pei. "Impact of Original Micro-Structure on Grind-Hardened Layer of 42CrMo Steel in Grind-Hardening." Materials Science Forum 878 (November 2016): 22–27. http://dx.doi.org/10.4028/www.scientific.net/msf.878.22.

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The grind-hardening test of 42CrMo steel was carried out on a forming grinding machine. The macrostructure, microstructures, micro-hardness and the depth of the hardened layer were measured and analyzed by optical micro-scope, scanning electron microscope and digital micro-hardness tester. The influences of original microstructure on the grind-hardened layer of 42CrMo steel were studied. The results show that the acicular martensite and a small amount of undissolved carbide appear in the surface layer, and slightly coarse martensite and a small amount of undissolved carbide appear in the middle layer of the completely hardened zone. Microstructure of the transitional zone varies with original structure. The microstructures and micro-hardness of the completely hardened zone have no obvious change under different original organizations, and the micro-hardness is 620HV0.5-700HV0.5. However, the distance from the slightly coarse martensite and the depth of the hardened layer increase with the uniformity improvement of the original microstructure.

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Muangjunburee, Prapas, Nutchanon Poolsiri, Sasirat Chaideesungnoen, Ammarat Naultem, Hein Zaw Oo, and Manwika Kongpuang. "XRD Observation on the Weld Metal of Resurfaced Rail Steel." Chiang Mai Journal of Science 50, no. 4 (2023): 1–11. http://dx.doi.org/10.12982/cmjs.2023.036.

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The current research studied two samples of rail steel grade 900A deposited with different electrodes, namely, electrodes A and B, using the Shielded Metal Arc Welding (SMAW) process. This research fi nds out the suitable hardness values of the various electrodes. The phase identifi cation and microstructural analysis of weld metal were conducted using X-ray diffraction (XRD) and an optical microscope, respectively. The micro-hardness profi les along the cross-section of the weldment were acquired using a micro-Vickers hardness tester, and a Brinell hardness tester measured the hardness values on the top surface of the weld metal. According to the results, the diffraction angles of the XRD patterns for all weld metal samples differed due to their distinct microstructures. The microstructure of the weld metal, in particular, produced the primary infl uence on the hardness

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Li, Yi, Chao Sun, Kai Liu, Tong Xu, and Binbin He. "Magnetic Evaluation of Heat-Resistant Martensitic Steel Subjected to Microstructure Degradation." Materials 15, no. 14 (2022): 4865. http://dx.doi.org/10.3390/ma15144865.

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The present paper investigates the use of the magnetic hysteresis loop technique to nondestructively evaluate microstructural degradation in heat-resistant martensitic (HRM) steels. The degradation impairs the safe operation of thermal power plants and it is thus essential to periodically assess it using nondestructive evaluation (NDE) techniques. In this contribution, HRM steels are thermally aged up to 16,000 h at 675 °C to simulate the microstructural degradation, then the changes in the magnetic coercivity, hardness, and microstructure are systematically characterized and the relations between them are determined. Both coercivity and hardness decrease with thermal aging duration, which can be interpreted in terms of the microstructure parameters’ evolution based on the pinning of crystal defects on domain walls and dislocations. Coercivity and hardness share the same softening trend with aging time, and good linear relations between coercivity, hardness, and microstructure parameters are found. These results provide a key to understanding the magnetic parameter evolution in HRM steels and suggest the possibility of using magnetic technologies for the NDE of microstructure degradation in thermal power plants.

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Bhowmik, Sumit, Prasanta Sahoo, Sanjib Kumar Acharyya, Sankar Dhar, and Jayanta Chattopadhyay. "Effect of Microstructure Degradation on Fracture Toughness of 20MnMoNi55 Steel in DBT Region." International Journal of Manufacturing, Materials, and Mechanical Engineering 6, no. 3 (2016): 11–27. http://dx.doi.org/10.4018/ijmmme.2016070102.

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The paper considers the effect of microstructure degradation on fracture toughness of 20MnMoNi55 pressure vessel steel. This degradation is reflected through the shift of fracture toughness vs. temperature curve along the temperature axis and rise in reference temperature in ductile to brittle transition (DBT) region. Hardness also depends on the microstructure of metallic alloys. The present study explores the correlation between hardness and fracture toughness for different microstructures in order to calibrate loss in toughness from hardness. The master curve reference temperature and microhardness for different microstructures are measured experimentally. It is observed that there exists a fair linear relation between microhardness and reference temperature.

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Akbari, G. H., H. Abbaszadeh, and H. Ghotbi Ravandi. "Effects of Al, Si and Mn on the Recrystallization Behaviors of Fe Containing 70B Brass." Materials Science Forum 558-559 (October 2007): 107–11. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.107.

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The effects of alloying elements and impurities on the microstructure and properties of metals and alloys are important. Understanding of these effects may help to control and produce products with desired properties at lower cost. In the present work the effects of Al, Si and Mn on the recrystallization behavior, hardness and microstructural changes of an Fe- containing brass during annealing were studied. The results show that alloying elements strongly affect recrystallization kinetics and resulted finer microstructures. Hardness variations during annealing are consistent with microstructural observations and the presence of alloying elements. All elements slow down recrystallization progress and increase resulted hardness values. The resulted microstructures in the presence of alloying elements are much finer than that of plain 70B brass. It was concluded that the present alloying elements affect the recrystallization behavior of 70B brass in a similar manner. Their mechanism of interactions is solute drag effect and their effects sum up when they present together.

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Anisimov, Evgeniy, Jan Manak, Maxim Puchnin, and Pavel Sachr. "The Effect of Microstructural Features on Mechanical Properties." Key Engineering Materials 606 (March 2014): 47–50. http://dx.doi.org/10.4028/www.scientific.net/kem.606.47.

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Every material is structured in its unique way and has its own recognizable microstructure. There are a number of approaches in establishing the relationship between mechanical properties and microstructure of a material, but none of them is universal and correlation free, probably because of luck of attention to the sub-grain structure. The possibility of calculating the hardness number using only geometric sizes of microstructural formations is discussed in this paper, where the grain is meant to be a container of the two most frequently occurred shapes in the microstructures globula and lamellae.

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Adachi, Yoshitaka, and Kaneaki Tsuzaki. "Ultra Rapid Softening of High Strength Structural Steels by Thermomechanical Treatment." Materials Science Forum 539-543 (March 2007): 4807–12. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.4807.

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This study aims to shorten the softening treatment period as possible in high strength structural steels. The steel used is SCM440 steel. As an initial microstructure, martensite, bainite, pearlite and complicated microstructure consisting of ultrafine polygonal, martensite and equiaxed cementite were extensively examined to understand their softening process on aging at 973K. These initial microstructures were prepared by heat or thermomechanical treatment. Their initial Vickers hardness (Hv(10kgf)) were 634, 281, 219 and 238, respectively. It is noteworthy that within five minutes on aging hardness of the complicated microstructure reached lower than Hv200, while it took more than several hours for other initial microstructures. A quantitative evaluation of microstructures appears to help in understanding the mechanism of the softening kinetics.

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Wang, Chan, Duoqi Shi, and Shaolin Li. "A Study on Establishing a Microstructure-Related Hardness Model with Precipitate Segmentation Using Deep Learning Method." Materials 13, no. 5 (2020): 1256. http://dx.doi.org/10.3390/ma13051256.

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This paper established a microstructure-related hardness model of a polycrystalline Ni-based superalloy GH4720Li, and the sizes and area fractions of γ’ precipitates were extracted from scanning electron microscope (SEM) images using a deep learning method. The common method used to obtain morphological parameters of γ’ precipitates is the thresholding method. However, this method is not suitable for distinguishing different generations of γ’ precipitates with similar gray values in SEM images, which needs many manual interventions. In this paper, we employ SEM with ATLAS (AuTomated Large Area Scanning) module to automatically and quickly detect a much wider range of microstructures. A deep learning method of U-Net is firstly applied to automatically and accurately segment different generations of γ’ precipitates and extract their parameters from the large-area SEM images. Then the obtained sizes and area fractions of γ’ precipitates are used to study the precipitate stability and microstructure-related hardness of GH4720Li alloy at long-term service temperatures. The experimental results show that primary and secondary γ’ precipitates show good stability under long-term service temperatures. Tertiary γ’ precipitates coarsen selectively, and their coarsening behavior can be predicted by the Lifshitz–Slyozov encounter modified (LSEM) model. The hardness decreases as a result of γ’ coarsening. A microstructure-related hardness model for correlating the hardness of the γ’/γ coherent structures and the microstructure is established, which can effectively predict the hardness of the alloy with different microstructures.

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Wang, Ying Hao, Xian Sheng Qi, Xian Lin Meng, et al. "The Influence of Initial Microstructures on the Diffusion Bonding Interface of High Nb Containing TiAl Alloy." Advanced Materials Research 753-755 (August 2013): 396–401. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.396.

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The solid-state diffusion bonding experiments of high Nb containing TiAl alloy were successfully carried out at 950°C under a uniaxial pressure of 30MPa for 45min, and the influence of different initial microstructures, such as initial forged microstructure (named duplex microstructure) with different grain sizes, near lamellar microstructure and full lamellar microstructure, on the interface of the bonding joints were investigated. And the microstructure characterization of interfaces was taken by OM, SEM, EDS and micro-hardness tester. The results indicated that the grain size and strain energy are of great importance to improve the quality of interfacial bonding. Besides, the interfacial microstructure was found different from matrix and changed during the diffusion bonding process. Meanwhile, micro-hardness tests of the three kinds of joints showed that the micro-hardness in the interface was slightly higher than matrix in all the joints, resulted from the working hardening of the interface under the uniaxial pressure.

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Zhang, Huayu, Zhiheng Wei, Fengqin Xie, and Baohai Sun. "Assessment of the Properties of AISI 410 Martensitic Stainless Steel by an Eddy Current Method." Materials 12, no. 8 (2019): 1290. http://dx.doi.org/10.3390/ma12081290.

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Based on electromagnetic theory, metallurgical characteristics can be detected by eddy current nondestructive testing technology. In this study, the relationship between the surface microstructure and the eddy current output of martensitic stainless steel AISI 410 was studied using this technology at different quenching temperatures. The mechanical properties include material hardness, microstructure types and microstructural changes after thermal treatment was evaluated. Using Vickers hardness as the surface hardness index of AISI 410 steel, the relationship between eddy current output signal, in terms of impedance and inductance, and sample surface hardness was studied and the effects of different quenching temperatures on the steel’s surface hardness was examined. In addition, the change of microstructure types of AISI 410 steel after thermal treatment was detected by the eddy current nondestructive testing method, and the results were verified by metallographic microscopy.

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Lan, Liang Yun, Chun Lin Qiu, and De Wen Zhao. "Analysis of the Hardness and Elastic Modulus Distribution in a High Strength Steel Welded Joint by Nanoindentation." Advanced Materials Research 189-193 (February 2011): 3270–73. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.3270.

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Nanoindentation technique was employed to study the hardness and elastic modulus for different regions in the welded joint of high strength steel. And the variation in mechanical behavior at micro scales was analyzed combined with microstructure observation. Experimental results showed that both maximum hardness (4.11GPa) and maximum elastic modulus (210.3GPa) were obtained in the coarse grained HAZ and the corresponding microstructure was granular bainite. While the weld metal and fine grained HAZ had similar values of hardness and elastic modulus, and corresponding microstructures were acicular ferrite and polygonal ferrite respectively.

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de Sousa, Guilherme Calixto Carneiro, Andrei de Paula, Andre Barros, Amauri Garcia, and Noé Cheung. "Hardness Changes Due to the Morphological Evolution of Microstructural Phases in an As-Solidified Zn-Fe Alloy." Materials 18, no. 6 (2025): 1311. https://doi.org/10.3390/ma18061311.

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Zn-Fe alloys are gaining attention for their use as bioabsorbable implants, and their development requires a deeper understanding of the processing–microstructure–property relationships. This study aimed to analyze the influence of microstructural features on the hardness of a Zn-2 wt.%Fe alloy. To achieve this, a casting was fabricated using directional solidification, and samples that experienced various cooling conditions were extracted from it. The results show that the microstructure of the investigated alloy was composed of a Zn-rich phase (matrix) and FeZn13 intermetallic particles. Four different morphological patterns of the microstructure could be formed, depending on the thermal conditions during solidification. For each of these patterns, a reduction in the spacing between FeZn13 particles, a parameter representing the degree of microstructural refinement, did not lead to a considerable increase in the hardness of the Zn-2wt.%Fe alloy. Hardness was shown to be more dependent on the morphology of the FeZn13 intermetallics and Zn-rich matrix than on the degree of refinement of these microstructural phases. Therefore, the present research provides valuable insights into the development of enhanced Zn-Fe alloys by demonstrating how microstructural features can affect their properties, particularly in terms of hardness and morphologies of the microstructural phases.

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Min, B., J. S. Song, J. H. Lee, B. J. Choi, K. M. Kim, and S. O. Kim. "Multiple Teeth Fractures in Dentinogenesis Imperfecta: A Case Report." Journal of Clinical Pediatric Dentistry 38, no. 4 (2014): 362–65. http://dx.doi.org/10.17796/jcpd.38.4.q523456j733642r2.

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Dentinogenesis imperfecta (DGI) is a hereditary defect consisting of opalescent teeth composed of irregularly formed and hypomineralized dentin. This paper presents the multiple fractures of DGI-affected teeth and suggests the reason of low fracture resistance by observing the dentin microstructures directly using scanning electron microscope (SEM) and by measuring its surface hardness using the Vickers hardness test. .SEM revealed that while the enamel microstructure was similar in the DGI-affected and normal teeth, the microstructure of the DGI-affected dentin was poorly woven and more loosely packed than that of the normal dentin. The Vickers hardness of the DGI-affected dentin was 4.89 times softer than the normal dentin. The low fracture resistance of DGI-affected teeth can be attributed to the poorly woven microstructure of their dentin, which leads to a reduction in hardness.

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Lekoadi, Paul, Monnamme Tlotleng, Kofi Annan, Nthabiseng Maledi, and Bathusile Masina. "Evaluation of Heat Treatment Parameters on Microstructure and Hardness Properties of High-Speed Selective Laser Melted Ti6Al4V." Metals 11, no. 2 (2021): 255. http://dx.doi.org/10.3390/met11020255.

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This study presents the investigation on how heat treatment parameters, which are temperature, cooling method, and residence time, influence the microstructural and hardness properties of Ti6Al4V components produced on Ti6Al4V substrate using high speed selective laser melting technique. Heat treatment was performed on the produced samples before they were characterized for microstructure and hardness. The microstructure of the as-built sample contained large columnar β-grains that were filled with martensite α’ phase and had a high hardness of 383 ± 13 HV. At 1000 °C and residence time of maximum 4 h, better heat treatment parameters were seen for the selective laser melting (SLM) produced Ti6Al4V sample since an improved lamellar α + β microstructure was obtained at this condition. This microstructure is known to have improved tensile properties.

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Shabgard, Mohammadreza, Hossein Ghasemzadeh, Behnam Khosrozadeh, and Andreas W. Momber. "Effects of core sand type and heat treatment on solid particle erosion of core box AISI H13 tool steel." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 231, no. 3 (2015): 309–19. http://dx.doi.org/10.1177/1464420715595653.

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The paper reports on investigations into the erosion, microstructural features, and material removal mechanisms of AISI H13 core boxes eroded by two types of core sand (silica and chromite). Different heat treatment operations are carried out, namely martempering, carbonitriding, quenching, and tempering, in order to vary hardness, microstructure, and surface morphology. Scanning electron microscopy inspections show that erosion is not only a function of surface hardness of the target material but also of its microstructure. Erosion of martensitic microstructure, consisting of very fine carbides with a uniform martensitic substructure, is much less severe than erosion of a material characterized by dispersed coarse carbide. Hardness effects on the erosion process are discussed in terms of material removal modes.

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Chi, Hongxiao, Jihao Liu, Jian Zhou, Dangshen Ma, and Jinbo Gu. "Influence of Microstructure on the Mechanical Properties and Polishing Performance of Large Prehardened Plastic Mold Steel Blocks." Metals 14, no. 4 (2024): 477. http://dx.doi.org/10.3390/met14040477.

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The microstructures throughout a 696 × 1360 mm cross-section of an ISO 1.2738 prehardened steel block for a plastic mold were characterized via optical and electron microscopy and electron backscatter diffraction. The hardness, strength, and polishing performance of the steel block were also tested. The results showed that the microstructure of the steel bloom from the edge to the core consisted of tempered sorbite, tempered bainite, and pearlite microstructures. Abnormal upper bainite and coarse carbides were also found. The bloom sections with hardness values of 37.4 to 39.3 HRC comprised tempered sorbite and bainite. The hardness of the core was approximately 36.5 HRC due to the presence of pearlite. The tensile and yield strengths were the same in the edge and middle areas mainly owing to tempered sorbite. The polishing performance was affected by the microstructure. Tempered sorbite produced the best polishing performance due to its fine and uniform microstructure, whereas that of tempered bainite and pearlite, which contained large carbide particles and mixed phases, was worse.

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Kim, Kwangsoo, Namhyun Kang, Minjung Kang, and Cheolhee Kim. "Assessment of Heat-Affected Zone Softening of Hot-Press-Formed Steel over 2.0 GPa Tensile Strength with Bead-On-Plate Laser Welding." Applied Sciences 11, no. 13 (2021): 5774. http://dx.doi.org/10.3390/app11135774.

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High-strength hot-press-formed (HPF) steels with a fully martensitic microstructure are being widely used in the fabrication of automotive body structure, and 2.0 GPa-strength HPF steel has recently been commercially launched. However, heat-affected zone (HAZ) softening is unavoidable in welding martensitic steel. In this study, the HAZ softening characteristic of 2.0 GPa HPF steel was investigated by applying a high-brightness laser welding process, wherein the heat input was controlled by varying the welding speed. Microstructural evaluation and hardness test results showed that the base metal with a fully martensitic microstructure was changed to the same type of fully martensitic microstructure in the weld metal, while relatively soft microstructures of tempered martensite and ferrite phase were partially formed in the intercritical HAZ (ICHAZ) and subcritical HAZ (SCHAZ) areas. In the tensile test, the joint strength was 10–20% lower than that of the base metal, and the fracture initiation was estimated at the ICHAZ/SCHAZ boundary, where the lowest hardness was confirmed by the nanoindentation technique.

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Wathanyu, Kessaraporn, and Siriporn Rojananan. "Microstructure, Hardness and Electrical Conductivity of Silver-Metal Oxides Electrical Contact Materials." Advanced Materials Research 486 (March 2012): 529–32. http://dx.doi.org/10.4028/www.scientific.net/amr.486.529.

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The aim of this paper was to study the microstructure, hardness and electrical conductivity of silver-metal oxides electrical contact materials. The Ag-SnO2, Ag-ZnO and Ag-CuO were prepared by powder metallurgy process. The density, microstructure, hardness and electrical conductivity were investigated. The results showed that the density of silver-metal oxides were 91-96% of theoretical density. The microstructures exhibited that the metal oxides were uniform dispersion in the silver matrix. The hardness of Ag-(5, 10)SnO2 and Ag-(5, 10)ZnO samples were about 100 HV and the hardness of Ag-(5, 10)CuO samples were about 88 HV. The Ag-5CuO samples had the highest electrical conductivity at the value of 91.27 %IACS.

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Tuz, Lechosław, Aneta Ziewiec, and Krzysztof Pańcikiewicz. "Influence of the Thermal Cutting Process on Cracking of Pearlitic Steels." Materials 14, no. 5 (2021): 1284. http://dx.doi.org/10.3390/ma14051284.

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The paper presents research results of the influence of heat input into high carbon rail steel during cutting processes on microstructure transformation and cracking. The massive block of steel prepared for rail rolling processes was cut and examined by nondestructive magnetic testing and destructive testing by microscopic examination and hardness measurements. The results show unfavorable microstructure changes where pearlite and transformed ledeburite were obtained. The effects of the presence of such microstructures are high hardness near to cutting surfaces (above 800 HV) and microcracks which grow into low hardness block cores during rolling and rail shaping.

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Detwal, Sudhanshu, and Deivanathan R. "Properties investigation of austempered ductile iron." Metallurgical and Materials Engineering 22, no. 1 (2016): 25–30. http://dx.doi.org/10.30544/137.

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This work concerns microstructural and mechanical properties of an austempered ductile cast iron (ADI). The ductile iron material was produced by the sand mould casting technique. Afterwards, austempering heat treatment was applied to the specimens at two different temperatures of 250°C and 350°C. Austempered Ductile Irons (ADIs) were produced successfully by different two-stage heat treatments, to obtain favorable microstructure and hardness. The microstructure and hardness obtained by such variable heat treatments were compared. The austempering temperature and time were found to be decisive parameters in obtaining a desired ADI microstructure.

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Faria, Jonas, Andrei de Paula, Cássio Silva, et al. "Fe-Containing Al-Based Alloys: Relationship between Microstructural Evolution and Hardness in an Al-Ni-Fe Alloy." Metals 13, no. 12 (2023): 1980. http://dx.doi.org/10.3390/met13121980.

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Recycled Al alloys not only offer environmental and economic benefits but also present a valuable base for the development of innovative materials, such as Al-Ni-Fe alloys. This work particularly focuses on the microstructural changes and hardness of an Al-5Ni-1Fe alloy (wt.%) solidified with an approximate 20-fold variation in cooling rates. For the various microstructural length scales obtained, only the eutectic regions exhibit a uniform pattern, with the eutectic colonies comprising an α-Al phase along with Al3Ni and Al9FeNi intermetallic compounds. It is shown that microstructural refinement can lead to a 36% increase in hardness. To represent this mathematically, hardness values are associated with the eutectic colony and intermetallic fiber spacings (λEC and λIF is, respectively) using experimental equations based on the Hall–Petch relationship and multiple linear regression. In addition, comparisons are undertaken with Al-5Ni and Al-1Fe (wt.%) alloy samples produced under the same conditions. The Al-5Ni-1Fe alloy exhibits higher hardness values than both the Al-5Ni and Al-1Fe binary alloys. Furthermore, the hardness of the ternary Al-Ni-Fe alloy is sensitive to microstructural refinement, a characteristic absent in the binary alloys. For λIF−1/2 = 1.56 µm−1/2 (coarser microstructure), the Al-5Ni-1Fe alloy exhibits a hardness of about 13% and 102% higher than that of the Al-5Ni and Al-1Fe alloys, respectively, while for λIF−1/2 = 1.81 µm−1/2 (finer microstructure), it demonstrates a hardness of approximately 39% and 147% higher as compared to that of the Al-5Ni and Al-1Fe alloys, respectively. Thus, this research provides experimental correlations that connect hardness, microstructure, and solidification thermal parameters, contributing to a better understanding for the design of as-cast Fe-contaminated Al-Ni-based alloys.

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Saha, Subrata, Naureen Binte Shahjahan, and Naseem Ahmed. "EFFECT OF PROCESS PARAMETERS ON HARDNESS, DEPTH OF HEAT AFFECTED ZONE AND MICRO STRUCTURE OF WELDMENT IN MIG WELDING." Journal of Mechanical Engineering 44, no. 2 (2015): 132–36. http://dx.doi.org/10.3329/jme.v44i2.21438.

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Electrode wire diameter, welding current, electrode wire feed rate, arc length are influential processparameters for hardness, depth of heat affected zone and microstructure of weldment in case of MIG weldingprocess. In this work, the effect of these process parameters on weldment characteristics had been studied.Experiments were conducted using bead-on surface of medium carbon steel plate in a semi-automatic MIGwelding machine. Hardness, depth of heat affected zone and microstructure of weldment were examined. Anartificial neural network (ANN) based modeling of the experiments had been successfully done to realize thepatterns of results obtained from the experiments. It had been observed that the microstructures obtained inthese weldments were distinctly different from that of the base metal. Microstructures, hardness and depth ofheat affected zone of weldment depends on the process parameters. ANN model shows good agreement with theexperimental results in case of hardness and depth of heat affected zone of weldment.

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Kunert, M., O. Kienzle, B. Baretzky, S. P. Baker, and E. J. Mittemeijer. "Hardness–depth profile of a carbon-implanted Ti–6Al–4V alloy and its relation to composition and microstructure." Journal of Materials Research 16, no. 8 (2001): 2321–35. http://dx.doi.org/10.1557/jmr.2001.0319.

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The variation of mechanical properties (hardness, indentation modulus) within a carbon-implanted region of a Ti–6Al–4V alloy—about 350-nm thick—was, for the first time, related with the microstructure and the chemical composition with a depth accuracy as small as ±20 nm. Microstructure, chemical composition, and mechanical properties of the implanted alloy were determined using transmission electron microscopy, Auger electron spectroscopy, and nanoindentation, respectively. The microstructure within the implanted region contains TiC precipitates, the density of which changes with depth in accordance with the carbon content. The hardness depends on the precipitate density: the maximum hardness occurs at the depth where an almost continuous TiC layer had formed. The depth profiles of hardness and indentation modulus were measured using three different methods: the cross-section method (CSM); the constant-load method (CLM); and the load-variation method (LVM). Only the hardness– depth profile obtained using the CSM, in which the indentations are performed perpendicular to the hardness gradient on a cross section of the specimen, reflects the microstructural variations present in the implanted region.

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Ahmed, Mohamed M. Z., Mohamed M. El-Sayed Seleman, Ebtessam Elfishawy, Bandar Alzahrani, Kamel Touileb, and Mohamed I. A. Habba. "The Effect of Temper Condition and Feeding Speed on the Additive Manufacturing of AA2011 Parts Using Friction Stir Deposition." Materials 14, no. 21 (2021): 6396. http://dx.doi.org/10.3390/ma14216396.

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In the current study, solid-state additive manufacturing (SSAM) of two temper conditions AA2011 was successfully conducted using the friction stir deposition (FSD) process. The AA2011-T6 and AA2011-O consumable bars of 20 mm diameter were used as a feeding material against AA5083 substrate. The effect of the rotation rate and feeding speed of the consumable bars on the macrostructure, microstructure, and hardness of the friction stir deposited (FSD) materials were examined. The AA2011-T6 bars were deposited at a constant rotation rate of 1200 rpm and different feeding speeds of 3, 6, and 9 mm/min, whereas the AA2011-O bars were deposited at a constant rotation rate of 200 mm/min and varied feeding speeds of 1, 2, and 3 mm/min. The obtained microstructure was investigated using an optical microscope and scanning electron microscope equipped with EDS analysis to evaluate microstructural features. Hardness was also assessed as average values and maps. The results showed that this new technique succeeded in producing sound additive manufactured parts at all the applied processing parameters. The microstructures of the additive manufactured parts showed equiaxed refined grains compared to the coarse grain of the starting materials. The detected intermetallics in AA2011 alloy are mainly Al2Cu and Al7Cu2Fe. The improvement in hardness of AA2011-O AMPs reached 163% of the starting material hardness at the applied feeding speed of 1 mm/min. The hardness mapping analysis reveals a homogeneous hardness profile along the building direction. Finally, it can be said that the temper conditions of the starting AA2011 materials govern the selection of the processing parameters in terms of rotation rate and feeding speed and affects the properties of the produced additive manufactured parts in terms of hardness and microstructural features.

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Fu, Bin Guo, Hong Wei Wang, Chun Ming Zou, Pan Ma, and Zun Jie Wei. "Microstructure and Hardness of High Temperature Alloy Ti-1100 Melted in CaO Crucible." Materials Science Forum 788 (April 2014): 158–63. http://dx.doi.org/10.4028/www.scientific.net/msf.788.158.

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A high temperature alloy Ti-1100 was produced by vacuum induction melting technology. The effects of casting modulus on the microstructure and hardness of the cast alloys were determined and the results were presented and briefly discussed. Results demonstrate that the microstructure of cast alloys with different modulus are all widmanstatten structure with basket weave features where individual α-laths are separated by a thin layer of retained prior β phase. The greater the modulus, the larger the prior β grain size and α-laths spacing, and the less the Vickers hardness. The roles of the casting modulus governing the microstructures and hardness of the alloys were also discussed.

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Esquivel, Rosalba, Miguel A. Suárez, Juan A. Alcántara, and J. Federico Chávez. "Microstructural Characterization of Al-Cu-Fe Alloys in the Quasicrystalline Composition Range." Materials Science Forum 691 (June 2011): 15–22. http://dx.doi.org/10.4028/www.scientific.net/msf.691.15.

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The microstructural changes of six Al-Cu-Fe alloys; A)Al62Cu25.5Fe12.5, B) Al65Cu20Fe15, C)Al68Cu20Fe12, D)Al61Cu26Fe13, E) Al65Cu22.5Fe12.5, F)Al64Cu25.5Fe13.5, where the icosahedral phase is present, have been experimentally studied in both as-cast and annealed conditions by X-ray diffractometry, optical metallography, scanning electron microscopy and hardness tests. The resulting microstructures were characterized to investigate the effect of chemical composition on percentage of icosahedral phase and the changes in hardness obtained in this composition range. It was found that the B) Al65Cu20Fe15alloy showed the microstructure with major amount of icosahedral phase in as-cast condition with a value of 50 area%, while the A) alloy showed the highest amount of icosahedral phase. The hardness of phases after heat treatment increased with respect to alloys in as-cast condition, the hardness of y-Al65Cu20Fe15phase increased between 20-25%, while the l-Al13Fe4 phase increased 9%.

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Azhar, Ahmad Zahirani Ahmad, Foo Tai Kong, Mohamad Hasmaliza, Manimaran Ratnam, and Zainal Arifin Ahmad. "Effect of Particle Sizes of Magnesium Oxide on Zirconia Toughened Alumina Vickers Hardness." Advanced Materials Research 173 (December 2010): 29–34. http://dx.doi.org/10.4028/www.scientific.net/amr.173.29.

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Vickers hardness of zirconia toughened alumina added MgO with different composition and particle size has been studied. Five different size of magnesium oxide particle at different composition (0.5 wt % to 0.9 wt %) were used in this experiment. Each batch of composition was mixed, uniaxially pressed into 13 mm pellets and sintered at 1600oC for 4 hours in pressureless conditions. Analysis of Vickers hardness, microstructural observation and EDX analysis has been carried out. Microstructural observation showed that the addition of magnesium oxide greatly affected zirconia toughened alumina microstructure. Smaller Al2O3 grain size is observed with the presence of MgO thus improving its mechanical properties such as hardness and density. Results of Vickers hardness increased linearly with addition of more MgO until a certain composition. Each particle size of MgO addition show different composition is needed to reach the optimum Vickers hardness, depending on the particle size. The increase of hardness of the cutting insert is mainly contributed by small sized Al2O3 grains due to the microstructure pinning effect introduced by MgO. Maximum Vickers hardness achieved in this experiment is 1710 Hv, obtained at 0.7 wt% MgO with 0.15 µm particle size.

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Ueno, Kouki, Akira Sato, and Hiroyuki Sato. "Formation of Microstructural Gradient of A2017 by RBT at Ambient Temperature." Materials Science Forum 794-796 (June 2014): 1233–38. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.1233.

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Distribution of microstructure and hardness by RBT (Rotary Bending and Tensile) loading at ambient temperature is presented. Grain size is one of the important parameters of microstructures of alloys, and affects mechanical characteristics depending on deformation conditions. At higher temperatures, coarsening of grain size improves creep strength, while the finer improve tensile strength at ambient temperature. Grain size shows opposite effect on strength of alloys depending on temperatures and not always possible to improve strength both at ambient and high temperatures. Authors have attempted microstructural control by formation of distribution of plastic strain prior to heat treatment of aluminum alloys to obtain well-balanced strength both at high and ambient temperatures. In this report, distribution of grain size and hardness in 2017 aluminum by RBT loading are presented, and compared with results in 1070 reported previously. RBT loading equipment is designed for combined loading by rotary bending and static tensile loading to distribute plastic strain. In 2017 alloy, obtained microstructure after suitable heat treatment show distribution of hardness, while grain size show homogeneous distribution. The distributions, however, are different from that in 1070 alloy.

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Li, Wen Bo, and Jing Wang. "Experimental Research on Hydrogen Resistance Performance of Different Microstructure." Materials Science Forum 932 (September 2018): 13–18. http://dx.doi.org/10.4028/www.scientific.net/msf.932.13.

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The paper studies the effects of different microstructures on the hydrogen resistance properties. Four kinds of microstructures were obtained by using four kinds of heat treatment processes for 45 steel materials. The mechanical properties of different microstructure materials were obtained by Vickers hardness test and internal residual stress test. The relationships between hardness and depth of four kinds of microstructures were obtained by stratified microhardness test. Static hydrogen resistance property of different microstructures was obtained by using the stripping method. Results show that the H2S corrosion layer of different microstructures is basically the same, and the depth and hardness distribution of the hydrogen embrittlement layer are quite different. More pearlite, lead to the weakness of hydrogen resistance property; quenched and tempered sorbite after the hydrogen corrosion is better than ferrite + pearlite structure, martensite has a good resistance to hydrogen permeability. Finally, the relationships between microhardness and depth of the hydrogen embrittlement layer with different microstructures were fitted.

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Wan Yusoff, Wan Yusmawati, Norliza Ismail, Nur Shafiqa Safee, Ariffin Ismail, Azman Jalar, and Maria Abu Bakar. "Correlation of microstructural evolution and hardness properties of 99.0Sn-0.3Ag-0.7Cu (SAC0307) lead-free solder under blast wave condition." Soldering & Surface Mount Technology 31, no. 2 (2019): 102–8. http://dx.doi.org/10.1108/ssmt-06-2018-0019.

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Purpose The purpose of this paper is to discuss the effect of a blast wave on the microstructure, intermetallic layers and hardness properties of Sn0.3Ag0.7Cu (SAC0307) lead-free solder. Design/methodology/approach Soldered samples were exposed to the blast wave by using trinitrotoluene (TNT) explosive. Microstructure and intermetallic layer thickness were identified using Alicona ® Infinite Focus Measurement software. Hardness properties of investigated solders were determined using a nanoindentation approach. Findings Microstructure and intermetallic layers changed under blast wave condition. Hardness properties of exposed solders decreased with an increase in the TNT explosive weight. Originality/value Microstructural evolution and mechanical properties of the exposed solder to the blast wave provide a fundamental understanding on how blast waves can affect the reliability of a solder joint, especially for military applications.

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Mikuš, Rastislav, Ivan Kováč, and Jozef Žarnovský. "Effect of Microstructure on Properties of NiCrBSi Alloys Applied by Flame-Powder Deposition." Advanced Materials Research 1059 (December 2014): 1–9. http://dx.doi.org/10.4028/www.scientific.net/amr.1059.1.

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This article deals with studying the relationships among the chemical composition, microstructure and properties (hardness, micro-hardness, wear resistance) of powder additives based on NiCrBSi after their deposition. Tested materials reached a relatively wide range of hardness after deposition, which corresponds to their chemical composition and microstructure. The abrasive wear resistance of materials was tested on an emery cloth. The results indicate that both the hardness and abrasive wear resistance of tested materials depend especially on the content of carbon and chromium. Microstructural analysis indicates that the structure of tested materials is formed by the γ-Ni solid solution and intermediate phases based on boron, silicon and carbon. Those mostly form eutectics (three types), or are excluded by precipitation. There was also found a significant effect of chromium, but especially carbon content on the ratio between the solid solution and eutectics in the microstructure of tested materials. These different ratios of solid solution and eutectics were markedly reflected in micro-hardness behaviours in deposited layers. Micro-hardness values confirmed also the presence of carbidic particles in the layers with carbon content higher than 0.7 wt%.

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Hossain, Rumana, Farshid Pahlevani, and Veena Sahajwalla. "Evolution of Microstructure and Hardness of High Carbon Steel under Different Compressive Strain Rates." Metals 8, no. 8 (2018): 580. http://dx.doi.org/10.3390/met8080580.

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Understanding the effect of high strain rate deformation on microstructure and mechanical property of metal is important for addressing its performance as high strength material. Strongly motivated by the vast industrial application potential of metals having excellent hardness, we explored the phase stability, microstructure and mechanical performance of an industrial grade high carbon steel under different compressive strain rates. Although low alloyed high carbon steel is well known for their high hardness, unfortunately, their deformation behavior, performance and microstructural evolution under different compressive strain rates are not well understood. For the first time, our investigation revealed that different strain rates transform the metastable austenite into martensite at different volume, simultaneously activate multiple micromechanisms, i.e., dislocation defects, nanotwining, etc. that enhanced the phase stability and refined the microstructure, which is the key for the observed leap in hardness. The combination of phase transformation, grain refinement, increased dislocation density, formation of nanotwin and strain hardening led to an increase in the hardness of high carbon steel.

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Mikami, Yoshiki, Masahito Mochizuki, Terumi Nakamura, Kazuo Hiraoka, and Masao Toyoda. "Application of Numerical Simulation Considering the Effect of Phase Transformation to the Estimation of Hardness Distribution in Welds." Materials Science Forum 512 (April 2006): 379–82. http://dx.doi.org/10.4028/www.scientific.net/msf.512.379.

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This study investigated a method for estimating hardness distribution in welds, considering the effect of phase transformation and weld thermal cycles. Hardness distribution in welds was estimated from fractions and hardness of each microstructure by using rule of mixture. Finite element heat conduction analysis was performed to calculate weld thermal cycles. Microstructures formed corresponding to the thermal cycle were also calculated based on the continuous cooling transformation (CCT) diagram. The method mentioned above was applied to welds of Ultra-Narrow Gap welding process, which was developed for welding of ultrafine-grained steels. The calculated thermal cycles in the welds corresponded with measured results. Moreover, the estimated hardness distribution in the welds, which were estimated by using calculated thermal cycles and the phase fraction of each microstructure, was also in good agreement with measured values.

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Babu, Purushothaman Dinesh, Gengusamynaidu Buvanashekaran, and Karupuudaiyar R. Balasubramanian. "EXPERIMENTAL STUDIES ON THE MICROSTRUCTURE AND HARDNESS OF LASER TRANSFORMATION HARDENING OF LOW ALLOY STEEL." Transactions of the Canadian Society for Mechanical Engineering 36, no. 3 (2012): 241–58. http://dx.doi.org/10.1139/tcsme-2012-0018.

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An experimental investigation with Nd:YAG laser system was carried out to study the effects of laser hardening process parameters on the microstructure and hardness during laser hardening of EN25 steel. The laser beam is allowed to scan on the surface of the work piece by varying the laser beam power (750–1250 W) and travel speed (500–1000 mm/min) of the work table. The microstructural features of the laser hardened EN25 steel were analysed using optical microscope. The microstructure of the surface layer was found to consist of plate martensite. A substantial increase in surface hardness was achieved, by a factor of 2 times the base material hardness.

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Błacha, S., M. St Węglowski, S. Dymek, and M. Kopuściański. "Microstructural Characterization and Mechanical Properties of Electron Beam Welded Joint of High Strength Steel Grade S690QL." Archives of Metallurgy and Materials 61, no. 2 (2016): 1193–200. http://dx.doi.org/10.1515/amm-2016-0198.

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Abstract In the paper the results of metallographic examination and mechanical properties of electron beam welded joint of quenched and tempered steel grade S690QL are presented. Metallographic examination revealed that the concentrated electron beam significantly affect the changes of microstructure in the steel. Parent material as a delivered condition (quenched and tempered) had a bainitic-martensitic microstructure at hardness about 290 HV0.5. After welding, the microstructure of heat affected zone is composed mainly of martensite (in the vicinity of the fusion line) of hardness 420 HV0.5. It should be noted, however, that the microstructure of steel in the heat affected zone varies with the distance from the fusion line. The observed microstructural changes were in accordance with the CCT-S transformation diagram for the examined steel.

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Yang, Jun, Mei Ling Chen, Li Yang, Huan Jin, and Hong Gao. "Study on Influence of Modified SiC Nano-Powders on the Microstructures and Work-Hardening Properties of ZGMn13." Advanced Materials Research 418-420 (December 2011): 558–62. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.558.

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The effects of modified SiC nano-powders on the microstructures and the work-hardening properties of shot peening treatment on high manganese steel have been carried out by means of microstructure observation, x-ray diffraction analysis and hardness testing. The results are showed that compared with the samples without modified SiC nano-powders, the microstructure of ZGMn13 are finer and markedly improved rate of work hardening. The micro-hardness of surface is enhanced significantly after the shot peening. Its strengthening mechanism is mainly twinning and dislocation, but no Martensite strengthening.

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Tekeli, Süleyman, Ijlal Simsek, Dogan Simsek, and Dursun Ozyurek. "Effects of Different Solid Solution Temperatures on Microstructure and Mechanical Properties of the AA7075 Alloy After T6 Heat Treatment." High Temperature Materials and Processes 38, no. 2019 (2019): 892–96. http://dx.doi.org/10.1515/htmp-2019-0050.

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AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.

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Kim, Jeong-Hun, Joonoh Moon, Sungwoo Cho, Namgi Gu, and Kangjun Yoon. "Microstructure and Mechanical Properties of SA508 Gr.3 Steel Cladded by GMAW using 309L and 308L Wires." Journal of Welding and Joining 43, no. 2 (2025): 185–93. https://doi.org/10.5781/jwj.2025.43.2.8.

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In this study, the microstructure and mechanical properties of GMAW cladded stainless steel layer on SA508 Gr.3 base steel were investigated. In SA508 base steel, black strip regions were observed with a higher concentration of alloying elements and a greater precipitation of carbides compared to the normal region, forming microstructure with a higher fraction of martensite. The fusion line (FL) between cladding layer and SA508 base steel was formed as a martensite layer, and unmixed region was observed near the FL. The 309L and 308L cladding layers exhibited complex solidification microstructures with cellular and vermicular morphologies. The microstructure was observed using optical microscopy (OM), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) analyses. Finally, the hardness distribution across the FL was evaluated and the correlation between microstructure and hardness was then analyzed.

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R., Jayachitra*. "CHARACTERIZATION OF MICROSTRUCTURE AND DETERMINATION OF ELASTIC PROPERTIES IN SAF 2205 DUPLEX STAINLESS STEEL USING ULTRASONIC MEASUREMENTS." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 5, no. 3 (2016): 863–73. https://doi.org/10.5281/zenodo.48381.

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Microstructural changes in duplex stainless steel due to changes in annealing temperature are characterized by ultrasonic pulse-echo technique and optical microscopy.  Duplex stainless steel was subjected to a series of heat treatments from 1100°C to 1350°C, followed by water quenching.  The microstructure after heat treatment at 1350°C resulted in coarse grained ferrite, which favored formation of Widmanstatan austenite with fast cooling.  Micro hardness and optical microscopy results are correlated with ultrasonic longitudinal and shear wave velocities, attenuation and ferrite count (%) in the specimens.  Ultrasonic velocities and micro hardness decrease with annealing temperature in the 1100°C - 1200°C range, while they increase slightly beyond 1200 up to 1350°C.  Ultrasonic attenuation exhibits an opposite behavior to velocity and hardness.  Fast Fourier Transform exhibit a decrease of the spectral amplitude in specimens with high heat treatment temperature. The results show that the use of Ultrasonic measurements to correlate the ultrasonic parameters with the microstructures and hardness is very fast and reliable.

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Jackson, Ben, Rob Torrens, Leandro Bolzoni, Fei Yang, Mike Fry, and Aamir Mukhtar. "Additive Manufacturing of Ti-6Al-4V with Added Boron: Microstructure and Hardness Modification." Key Engineering Materials 770 (May 2018): 165–73. http://dx.doi.org/10.4028/www.scientific.net/kem.770.165.

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Titanium alloy composites with titanium boride (TiB) discontinuous reinforcement have shown improved performance in terms of strength, stiffness, and hardness. Producing this composite through selective laser melting (SLM) can combine the advantages of freeform design with the ability to produce TiB reinforcement in-situ. In this study, SLM was used to consolidate a pre-alloyed Ti-6Al-4V (Ti64) and amorphous boron (B) powder mixture with the intent of producing 1.5wt% TiB reinforcement in a Ti64 matrix. The processing parameters of laser power and scanning speed were investigated for their effect on the density, microstructures, and hardness of the composite material. The results showed that the boron and Ti64 composite could achieve a density greater than 99.4%. Furthermore, it was found that processing parameters changed the microstructural features of the material. The higher the energy density employed the more homogenous the distribution of boron modified material. Macro features were also observed with laser paths being clearly evident in the subsurface microstructure. Micro-hardness testing and density measurement also showed a corresponding increase with increasing energy density. Maximum hardness of 392.4HV was achieved in the composite compared to 354.2HV in SLM fabricated Ti64.

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Heidarzadeh, Akbar, Mousa Javidani, Mohammadreza Mofarrehi, Amir Farzaneh, and X. Grant Chen. "Submerged Dissimilar Friction Stir Welding of AA6061 and AA7075 Aluminum Alloys: Microstructure Characterization and Mechanical Property." Metals 11, no. 10 (2021): 1592. http://dx.doi.org/10.3390/met11101592.

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The possibility of underwater dissimilar friction stir welding of AA6061 and AA7075 aluminum alloy was explored to overcome the problem of hardness loss in different microstructural zones. Optical microscopy and electron backscattered diffraction were employed to characterize the microstructure of the joint. Vickers hardness measurements were conducted on the cross-section of the joint to evaluate the mechanical strengths. The results showed that the microstructure of the AA7075 side had undergone the same mechanisms as those occurring during conventional friction stir welding. In the case of the AA6061 side, in addition to typical restoration mechanisms, the grain subdivision was observed. The AA7075 side had finer grains compared to the AA6061 side, which may be related to the different morphology and size of precipitates. Moreover, friction stir welding caused a reduction in the hardness values in all the microstructural areas compared to those of corresponding base materials. For example, it caused a reduction in the hardness of a thermomechanically affected zone from 105 HV to 93 HV in the AA6061 side, and from 187 HV to 172 HV in the AA7075 side. The underwater media improved the overall hardness values in thermo-mechanically affected zones (13% reduction in hardness) compared to those reported in literature (57% reduction in hardness).

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Yuan, Kuiwen, Jiaxin Chen, Dan Yang, and Zhiqing Zhang. "Effect of Annealing Process on the Microstructure and Texture of Cold-Rolled High-Purity Al-0.5%Cu Plates." Materials 15, no. 10 (2022): 3489. http://dx.doi.org/10.3390/ma15103489.

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As a kind of typical high stacking fault energy materials, recrystallization behavior of high purity Al-0.5%Cu alloy is significantly influenced by the annealing process. In this study, different heating rate, target temperature, and holding time were discovered to have profound impact on the microstructures and textures of Al-0.5%Cu plates. Electron backscatter diffraction (EBSD), scanning electron microscope (SEM), and X-ray diffraction (XRD) were utilized for analyzing the evolution of the microstructure and texture in the subsequent microstructural characterization. Vickers hardness tests were employed for measuring hardness of specimens. The results showed that no obvious recrystallization was observed at lower temperature and the composition of texture influenced by rising temperature, heating rate affected initial recrystallization temperature, grain size, and strength of textures. After recrystallizing completely, the size of microstructures and the distribution of textures had little change with the extension of holding time.

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