Journal articles: 'Mg2Si'

1

Nordin, Nur Azmah, Saeed Farahany, T. Abubakar, and Esah Hamzah. "Alteration by Cerium Element on Primary and Eutectic Mg₂Si Phases in Al-20%Mg₂Si In Situ Composite." Advanced Materials Research 1125 (October 2015): 23–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.23.

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Owing to its beneficial material properties, Al-Mg2Si in-situ composite has recently received wide attention and application in the manufacture of automotive and aerospace components. Melt treatment of the in-situ composite with the addition of Ce has resulted in a change in the primary and eutectic Mg2Si phases to refined morphology, which would be expected to improve the mechanical properties of the composite. Characteristic parameters of Mg2Si particles have been investigated via thermal and microstructural analysis. This has revealed that the addition of 0.8wt.% Ce produced optimum refinement effects on Mg2SiP because the coarse structure has been changed to a polygonal shape and reduced in size. Similarly, the flake-like morphology of Mg2SiE has been transformed into a rod-like or fibre form in addition to reduction of the eutectic cell area. The result also showed an increase in nucleation temperature TN of Mg2SiP while depressed for Mg2SiE, which also corresponds to the refinement morphology effect.

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Chegini, Mahdi, Mohammad Shaeri, Reza Taghiabadi, Sajjad Chegini, and Faramarz Djavanroodi. "The Correlation of Microstructure and Mechanical Properties of In-Situ Al-Mg2Si Cast Composite Processed by Equal Channel Angular Pressing." Materials 12, no. 9 (May 12, 2019): 1553. http://dx.doi.org/10.3390/ma12091553.

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In this paper, the effect of equal channel angular pressing (ECAP) on microstructure and mechanical properties of hypereutectic Al-20%Mg2Si and Al-15%Mg2Si, as well as hypoeutectic Al-10%Mg2Si composites has been investigated. After fabricating the composites by in-situ casting, the composites were processed using the ECAP process up to two passes at room temperature. Microstructural studies have been carried out using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. Mechanical properties were also documented using Vickers microhardness and shear punch tests. In the hypereutectic composites, a decrease in the average size of pro-eutectic Mg2Si (Mg2Sip) particles, breakages in eutectic networks, and lengthening of the Al (α) phase in direction of shear bands were observed after the ECAP process. For instance, the average size of Mg2Sip Particles in Al-20%Mg2Si composite reduced from 40 to 17 μm after 2 passes of ECAP. Furthermore, a uniform distribution of Mg2Sip particles was developed in the matrix. In hypoeutectic composite, the ECAP process caused a uniform distribution of eutectic Mg2Si (Mg2SiE) in the matrix that considered a favorable microstructure. Microhardness measurements and shear punch results showed an ascending trend after each pass of ECAP for all specimens. For example, microhardness and shear strength of Al-20%Mg2Si increased from 88 HV and 109 MPa to 119 HV and 249 MPa after two passes indicating 35% and 34% increments, respectively. Density and porosity calculations by Archimedes principle revealed that the density of the composites increased after two passes of ECAP due to the reduction of porosity.

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Aizawa, Tatsuhiko, Ren Bo Song, and Atsushi Yamamoto. "Thermoelectric Material Design in Pseudo Binary Systems of Mg₂Si – Mg₂Ge – Mg₂Sn on the Powder Metallurgy Route." Materials Science Forum 534-536 (January 2007): 1553–56. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.1553.

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Fundamental studies on the thermoelectricity have been mainly done in the pseudo binary systems of Mg2Si – Mg2Ge – Mg2Sn. In recent years, their thermoelectricity is revisited because of light-weight, low initial const and short turning back time in addition to high potential in figureof- merit for ZT approaching to unity or more. Conventional melting and solidification, or, normal PM routes fail in precise, wide-range control of chemical composition and microstructure control. New PM route via bulk mechanical alloying is developed to fabricate the solid solution semiconductive materials with Mg2Si1-xGex and Mg2Si1-ySny for 0 < x, y < 1 and to investigate their thermoelectric materials. Since Mg2Si is n-type and both Mg2Ge and Mg2Sn are p-type, pntransition takes place at the specified range of germanium content, x, and tin content, y. Through optimization of chemical composition, solid-solution type thermoelectric semi-conductive materials are designed both for n- and p-type materials. In addition, appropriate doping condition can be searched in the specified range of x and y.

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Kasai, Hidetaka, Lirong Song, Henrik Lyder Andersen, Hao Yin, and Bo Brummerstedt Iversen. "Multi-temperature structure of thermoelectric Mg2Si and Mg2Sn." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 73, no. 6 (November 24, 2017): 1158–63. http://dx.doi.org/10.1107/s2052520617014044.

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A multi-temperature structural study of Mg2Si and Mg2Sn was carried out from 100 to 700 K using synchrotron X-ray powder diffraction. The temperature dependence of the lattice parameters can be expressed as a = 6.3272 (4) + 6.5 (2) × 10−5 T + 4.0 (3) × 10−8 T 2 Å and a = 6.7323 (7) + 8.5 (4) × 10−5 T + 3.8 (5) × 10−8 T 2 Å for Mg2Si and Mg2Sn, respectively. The atomic displacement parameters (ADPs) are reported and analysed using a Debye model for the averaged U iso giving Debye temperatures of 425 (2) K for Mg2Si and 243 (2) K for Mg2Sn. The ADPs are considerably smaller for Mg2Si than for Mg2Sn reflecting the weaker chemical bonding in the Mg2Sn structure. Following the heating, an annealing effect is observed on the lattice parameters and peak widths in both structures, presumably due to changes in the crystal defects, but the lattice thermal expansion is almost unchanged by the annealing. This work provides accurate structural parameters which are of importance for studies of Mg2Si, Mg2Sn and their solid solutions.

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Fu, Xuesong, Yan Yang, QuanYang Ma, Xiaodong Peng, and Tiancai Xu. "Microstructure and Mechanical Behavior of Mg-0.5Si-xSn Alloys." Archives of Foundry Engineering 17, no. 4 (December 20, 2017): 179–84. http://dx.doi.org/10.1515/afe-2017-0154.

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AbstractMg-0.5Si-xSn (x=0.95, 2.9, 5.02wt.%) alloys were cast and extruded at 593K (320oC) with an extrusion ratio of 25. The microstructure and mechanical properties of as-cast and extruded test alloys were investigated by OM, SEM, XRD and tensile tests. The experimental results indicate that the microstructure of the Mg-0.5Si-xSn alloys consists of primary α-Mg dendrites and an interdendritic eutectic containing α-Mg, Mg2Si and Mg2Sn. There is no coarse primary Mg2Si phase in the test alloys due to low Si content. With the increase in the Sn content, the Mg2Si phase was refined. The shape of Mg2Si phase was changed from branch to short bar, and the size of them were reduced. The ultimate tensile strength and yield strength of Mg-0.52Si-2.9Sn alloy at the temperature of 473K (200oC) reach 133MPa and 112MPa respectively. Refined eutectic Mg2Si phase and dispersed Mg2Sn phase with good elevated temperature stability are beneficial to improve the elevated temperature performance of the alloys. However, with the excess addition of Sn, large block-like Mg2Sn appears around the grain boundary leading to lower mechanical properties.

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6

Rzychoń, T., and B. Dybowski. "The Influence of Aluminum on the Microstructure and Hardness of Mg-5Si-7Sn Alloy." Archives of Metallurgy and Materials 61, no. 1 (March 1, 2016): 425–32. http://dx.doi.org/10.1515/amm-2016-0077.

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Magnesium alloys due the low density and good mechanical properties are mainly used in the automotive and aerospace industry. In recent years, magnesium alloys are extensively developed for use in high temperatures (above 120°C). Among these alloys, magnesium alloys containing tin and silicon have large possibilities of application due to the formation of thermally stable intermetallic Mg2Sn and Mg2Si. In this paper the influence of aluminum and heat treatment on the on the microstructure and hardness of Mg-7Sn-5Si alloy is reported. It was found that the microstructure of Mg-7Sn-5Si alloy consist of α-Mg solid solution, Mg2Sn and Mg2Si compounds. Addition of 2 wt% of Al to Mg-7Sn-5Si alloy causes the formation of Al2Sn phase. Moreover, Al dissolves in the α-Mg solid solution. The solution heat-treatment of tested alloys at 500°C for 24 h causes the dissolve the Mg2Sn phase in the α-Mg matrix and spheroidization of Mg2Si compound. The Mg2Si primary crystals are stable at solution temperature. After ageing treatment the precipitation process of equilibrium Mg2Sn phase was found in both alloys. The addition of aluminum has a positive effect on the hardness of Mg-7Sn-5Si alloy. In case of Mg-5Si-7Sn-2Al alloy the highest hardness was obtained for sample aged for 148 h at 250°C (88 HV2), while in case of Al-free alloy the highest hardness is 70 HV for material aged for 148 h at 250°C.

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7

Rzychoń, Tomasz. "Microstructure of Hypereutectic Mg-Si Alloy with Sn, Al and Mn Additions." Solid State Phenomena 229 (April 2015): 65–70. http://dx.doi.org/10.4028/www.scientific.net/ssp.229.65.

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In the present study, the microstructure of Mg-5Si alloys with tin, aluminum and manganese was investigated. The microstructure of Mg-5Si alloy consists of the primary coarse Mg2Si phase, α-Mg solid solution and eutectic α-Mg + Mg2Si in which the eutectic Mg2Si phase solidifies in the form of Chinese script particles. The Mg2Sn phase and α-Mg solid solution with tin appear in the microstructure, when 7 wt.% of Sn was added to the Mg-5Si alloy. Aluminum dissolve in the α-Mg matrix and participates in the formation of Al2Sn phase. The addition of manganese promotes the formation of Mn5Si3 compound.

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8

Rzychoń, Tomasz, Bartosz Chmiela, Adrian Mościcki, Bartłomiej Dybowski, and Sylwia Jendrysko. "The Influence of Heat Treatment on the Microstructure and Hardness of Mg-5Si-7Sn-5Mn Alloy." Solid State Phenomena 229 (April 2015): 83–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.229.83.

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The microstructure and hardness of as-cast Mg-5Si-7Sn-5Mn alloy after solution and ageing treatments is presented in this paper. It was found that the microstructure of as-cast alloy. is composed of primary dendrites crystals of Mg2Si phase, α-Mg matrix, long needle-like precipitates of Mn5Si3, Chinese script particles of Mg2Si phase and irregular Mg2Sn phase. The solution treatment at 500°C causes the dissolution of the Mg2Sn phase in the α-Mg magnesium solid solution, whereas the remaining intermetallic compounds are stable in this temperature. The hardness of alloy increases from 73 HV2 to 96 HV2 at 250°C. The increase in hardness is a result of the formation of the lath-like precipitates of Mg2Sn phase within the α-Mg matrix.

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9

Song, Dae Hyun, C. W. Lee, K. Y. Nam, S. W. Lee, Y. H. Park, Kyung Mok Cho, and Ik Min Park. "Microstructural Characteristics and Creep Properties of Mg-5Al-2Si Alloys Modified with Sn and Sr." Materials Science Forum 539-543 (March 2007): 1784–89. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.1784.

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The effects of tin (Sn) and strontium (Sr) additions on the microstructure and creep properties of Mg-5Al-2Si (AS52) alloys were investigated. Results showed that the addition of Sn did not affect the morphology of secondary phase Mg2Si particles but induced the fine and uniform precipitation of thermally stable Mg2Sn at the grain boundary in the AS52 alloys. However, the morphology modification of the secondary phase Mg2Si particles from Chinese script shape to refined polygonal shape was greatly affected by the addition of Sr. Tensile strength and creep resistance were improved and tensile elongation was also increased in the modified alloy with addition of both Sr and Sn. Sn is the effective element for precipitating thermally stable Mg2Sn finely and uniformly at the grain boundary and Sr is the effective element for refining microstructure. Therefore both Sn and Sr are effective for modifying the microstructure and improving the creep properties of AS52 alloys.

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10

Uematsu, Yoshihiko, Keiro Tokaji, and Mitsutoshi Kamakura. "Fatigue Behaviour of Extruded Mg₂Si-Reinforced Magnesium Alloy." Key Engineering Materials 345-346 (August 2007): 223–26. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.223.

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Rotary bending fatigue tests were conducted in order to investigate the fatigue behaviour and fracture mechanisms of extruded Mg2Si-reinforced magnesium (Mg) alloys. Mg2Si particles were mixed with Mg alloy (AZ31) powder to form billets and then extruded at two different working temperatures of 685K and 646K, where the materials extruded at high and low temperatures were denoted as Mg2Si-H and Mg2Si-L, respectively. The grains of the matrix were finer in Mg2Si-L than in Mg2Si-H. The proof stress and tensile strength were independent of working temperature and increased compared with a conventional extruded AZ31 alloy, with a decreased in ductility. The fatigue strength of Mg2Si-H was almost the same as that of the extruded AZ31 alloy, but the fatigue limit was lower, while the fatigue strength of Mg2Si-L was higher than that of Mg2Si-H and the extruded AZ31 alloy. Both crack initiation and crack growth resistances in Mg2Si-L were improved, which could be attributed to high bonding strength of Mg2Si/Mg interfaces and fine grain refinement of the matrix.

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11

Konotopskyi, L. E., I. A. Kopylets, V. A. Sevrykova, E. N. Zubarev, and V. V. Kondratenko. "Features of Mg2Si Layer Growth in Si/Mg2Si Multilayers." Journal of Nano- and Electronic Physics 8, no. 2 (2016): 02021–1. http://dx.doi.org/10.21272/jnep.8(2).02021.

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12

Zhang, Chang Hua, and Zhi Qiang Yu. "Effects of Sputtering Power on the Microstructure of Mg₂Si Films by Magnetron Sputtering." Advanced Materials Research 287-290 (July 2011): 2298–301. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2298.

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Epitaxial films of magnesium silicide Mg2Si are prepared by magnetron sputtering system on Si (111) substrates. The crystal structures and the surface morphology of the Mg2Si films are characterized by X-ray diffraction and Field emission scanning electron microscope. The microstructure of Mg2Si films is obtained. The results show that the Mg2Si films have a strong Mg2Si (220) preferential orientation with sputtering power increases, the Mg2Si (220) peak intensity increases with increasing sputtering power before 100W and then decreases with increasing sputtering power.

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13

Liu, Xiaobo, Miao Yang, Dekun Zhou, and Yuguang Zhao. "Microstructure and Wear Resistance of Mg2Si–Al Composites Fabricated Using Semi-Solid Extrusion." Metals 10, no. 5 (May 2, 2020): 596. http://dx.doi.org/10.3390/met10050596.

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In situ Mg2Si–Al composites were prepared by using gravity casting and semi-solid extrusion. After P modification, the primary Mg2Si transformed to polygonal blocks. Extraction tests showed that the Mg2Si crystals had octahedral and tetrakaidekahedral morphologies. The semi-solid microstructure of the double-spheroidized α-Al matrix and reinforced-phase Mg2Si was successfully obtained by using semi-solid extrusion. Extraction tests showed that the Mg2Si crystals had a spherical morphology. Dry sliding wear behaviors of in situ Mg2Si–Al composites fabricated by using gravity casting and semi-solid extrusion with isothermal heat treatment holding times of 50, 60, and 160 min against 45 steel, under conditions of different sliding speeds and loads, were investigated. The worn surfaces were analyzed using SEM and EDS techniques. The results showed that Mg2Si–Al composites fabricated by using semi-solid extrusion were superior in terms of wear resistance to Mg2Si–Al composites fabricated by using gravity casting, because the former had uniformly distributed spherical reinforced phase particles of Mg2Si with weaker stress concentration around the particles, delaying the generation and expansion of cracks. The Mg2Si particles were not easily detached from the matrix, and once they fell off, the Mg2Si particles only served as spherical abrasive grains, with relatively small cutting and wear properties for the composite material. It was found that the Mg2Si/Al composite fabricated by using semi-solid extrusion with an isothermal heat treatment holding time of 60 min had the best wear resistance. The failure mechanisms of Mg2Si/Al composites were found to be mainly adhesive wear and abrasive wear.

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14

Liu, Zheng, and Xiao Mei Liu. "Research on Wear Resistance of Mg₂Si Reinforced Hypereutectic Al-Si Alloy Composite." Advanced Materials Research 619 (December 2012): 553–56. http://dx.doi.org/10.4028/www.scientific.net/amr.619.553.

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Mg2Si particle reinforced hypereutectic Al-Si composite was prepared by casting, and the microstructure and wear resistance of the composite were researched. The results indicated that the morphology of Mg2Si obviously changed with Mg2Si contents increasing, in which the morphology of Mg2Si in the composite had changed from polygon block to characters like and finally became coarse dendrite. There were effects of Mg2Si content and morphology on the wear resistance in the composite, which had the higher hardness and better wear resistance at the suitable Mg2Si content.

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15

Rzychoń, Tomasz, and Radosław Janik. "The Influence of Calcium on the Primary Mg₂Si Phase in the Hypereutectic Mg-Si Alloys." Solid State Phenomena 229 (April 2015): 71–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.229.71.

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The microstructure of Mg-5Si alloy consists of the primary coarse Mg2Si phase, α-Mg solid solution and eutectic α-Mg + Mg2Si, in which eutectic Mg2Si phase solidifies in the form of Chinese script particles. When 0.2 wt.% of Ca was added to the Mg-5Si alloy the size of primary Mg2Si phase remained unchanged. The modification effect of calcium on the primary Mg2Si phase was effective only in the Mg-5Si-0.5Ca alloy. The morphology of the primary Mg2Si phase is changed from the coarse dendrite shape to polyhedral shape and the size of primary crystals is significantly reduced. The addition of 0.6 wt.% Ca to Mg-7Si alloy did not cause the modification of primary Mg2Si phase.

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16

Xiao, Qing Quan, Quan Xie, Ke Jie Zhao, and Zhi Qiang Yu. "Effect of Annealing Atmosphere on the Mg₂Si Film Growth Deposited by Magnetron Sputtering." Advanced Materials Research 129-131 (August 2010): 290–94. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.290.

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Semiconducting Mg2Si films were fabricated on Si (111) substrates by magnetron sputtering and subsequent annealing, and the effects of annealing atmosphere on the Mg2Si film growth were studied. The structural and morphological properties of Mg2Si films were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that annealing atmosphere was an important factor that affected the growth of Mg2Si thin films, and vacuum annealing was not suitable for preparing Mg2Si thin films. Only Si (111) substrate diffraction peaks were observed, and no Mg2Si diffraction peak was observed when the first six Mg/Si samples were annealed under vacuum annealing condition. However, many Mg2Si diffraction peaks were observed besides the Si substrate diffraction peaks when the second six Mg/Si samples were annealed under Ar gas atmosphere. In addition, compact and smooth Mg2Si thin films annealed under Ar gas atmosphere were obtained.

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17

Yang, Mei Jun. "Preparation and Electrical Property of Mg₂Si Thin Film by Pulsed Laser Deposition." Advanced Materials Research 1058 (November 2014): 244–47. http://dx.doi.org/10.4028/www.scientific.net/amr.1058.244.

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Mg2Si thin film on Si(100) substrate was obtained by pulsed laser deposition. Effects of the annealing procedure on the growth of Mg2Si film were discussed. X-ray, atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) were applied for the phase and microstructure of the obtained Mg2Si film. The results revealed that the annealing procedure was very important for the crystallization of Mg2Si thin film. The Ar partial pressure of 10Pa, temperature of 500°C and time of 30min for annealing were the optimal annealing parameters for Mg2Si thin film formation. Furthermore, electrical properties of the obtained Mg2Si thin film were detected. The results showed that the maximal resistivity of Mg2Si thin film was 7Ω·cm within the temperature range of 110~230°C. And the resistivity gradually decreased with the increase of temperature, which was the characteristic behaviour of a semiconductor. Carrier concentration of the film was negative in the temperature range of testing, showing Mg2Si thin film as n-type semiconductor.

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18

Geng, Hao Ran, Peng Liu, Hua Wei Jiang, and Bo Teng. "Effects of Si on Structure and Properties of Mg-Sn Alloy." Applied Mechanics and Materials 320 (May 2013): 303–7. http://dx.doi.org/10.4028/www.scientific.net/amm.320.303.

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Magnesium alloys are becoming ever more prevalent in automotive and aerospace industries as energy conservation and performance demands increase. However, it is limited on further application in the automotive field for its low strength compared with steel and aluminum alloys. Effects of Si addition on microstructure and mechanical properties of as-cast Mg-5%Sn magnesium alloy were also studied using SEM, XRD and tensile testing. The results show that the phases of as-cast alloy are composed of α-Mg, Mg2Sn; Mg2Si. The addition of Si suppresses the precipitation of the Mg2Sn, Product Chinese character shape phases of Mg2Si. With the increase of Si content, the effect becomes more apparent. When Si content is up to 1.25wt%, the grain refining effect reached best level. The average alloy grain size reduced from 90μm to 30μm, the tensile strength is the highest. The average tensile strength increased from 128 MPa to 156 MPa. When the Si added at 1.25wt% or less, the hardness and strength were improved with the increase of Si. When 1.25% Si was added, grain did not become further refinement. While Si content was continue to be increase, the tensile strength decreased.

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19

Liu, Zheng, Xiao Mei Liu, and Min Xie. "Effect of Mg₂Si Contents on Microstructure of Mg₂Si Particle Reinforced Hypereutectic Al-Si Alloy Composites." Applied Mechanics and Materials 66-68 (July 2011): 160–63. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.160.

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Mg2Si particle reinforced hypereutectic Al-Si composite was prepared by direct melt reaction, and the effects of Mg2Si content on the microstructure of the composite were researched. The results indicated that the morphology of Mg2Si obviously changed with Mg2Si contents increasing, in which the morphology of Mg2Si in the composite had changed from polygon block to characters like and finally became coarse dendrite. Formation of α-Al grains in the composites with the high Si and Mg content was discussed.

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Malik, M. A., K. Majchrzak, and K. N. Braszczyńska-Malik. "Microstructural Analysis of AM50/Mg2Si Cast Magnesium Composites." Archives of Foundry Engineering 12, no. 4 (December 1, 2012): 109–12. http://dx.doi.org/10.2478/v10266-012-0116-8.

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Abstract AM50/Mg2Si composites containing 5.7 wt. % and 9.9 wt. %. of Mg2Si reinforcing phase were prepared successfully by casting method. The microstructure of the cast AM50/Mg2Si magnesium matrix composites was investigated by light microscopy and X-ray diffractometry (XRD). The microstructure of these composites was characterized by the presence of α-phase (a solid solution of aluminium in magnesium), Mg17Al12 (γ-phase), Al8Mn5 and Mg2Si. It was demonstrated that the Mg2Si phase was formed mainly as primary dendrites and eutectic.

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Liu, Zheng, Hong Biao Xu, Kai Cao, and Mei Yan Huang. "Effect of Isothermal Holding in Solid-Liquid Phase Region on Mg₂Si Morphology in Hypereutectic Al-Si In Situ Composite." Advanced Materials Research 430-432 (January 2012): 711–14. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.711.

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Mg2Si reinforced hypereutectic Al-Si in-situ composite was prepared and the effects of the isothermal holding temperature and time on Mg2Si in the composite were researched. The results showed that there were the important effects of holding temperature and time in the solid-liquid phase region of the Al-Si alloy on the size and morphology of Mg2Si. The size and morphology of Mg2Si became smaller and round with the rising of the holding temperature and prolonging of the holding time. The suitable technology in the test was obtained, in which when being held at 615°C for 300s, the size of Mg2Si decreased to 20.54μm and the shape factor of Mg2Si reached about 0.67.

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Zhao, Zhanyong, Shijie Chang, Jie Wang, Peikang Bai, Wenbo Du, and Wenjie Zhao. "First-Principles Study on Graphene/Mg2Si Interface of Selective Laser Melting Graphene/Aluminum Matrix Composites." Metals 11, no. 6 (June 10, 2021): 941. http://dx.doi.org/10.3390/met11060941.

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The bonding strength of a Gr/Mg2Si interface was calculated by first principles. Graphene can form a stable, completely coherent interface with Mg2Si. When the (0001) Gr/(001) Mg2Si crystal plane is combined, the mismatch degree is 5.394%, which conforms to the two-dimensional lattice mismatch theory. At the interface between Gr/Mg2Si, chemical bonds were not formed, there was only a strong van der Waals force; the interfaces composed of three low index surfaces (001), (011) and (111) of Mg2Si and Gr (0001) have smaller interfacial adhesion work and larger interfacial energy, the interfacial energy of Gr/Mg2Si is much larger than that of α-Al/Al melt and Gr/Al interfacial (0.15 J/m2, 0.16 J/m2), and the interface distance of a stable interface is larger than the bond length of a chemical bond. The interface charge density difference diagram and density of states curve show that there is only strong van der Waals force in a Gr/Mg2Si interface. Therefore, when the Gr/AlSi10Mg composite is stressed and deformed, the Gr/Mg2Si interface in the composite is easy to separate and become the crack propagation source. The Gr/Mg2Si interface should be avoided in the preparation of Gr/AlSi10Mg composite.

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Fan, Wen Hao, Rui Xue Chen, Pei De Han, and Qing Sen Meng. "First-Principle Study of Electronic Structures of Y-Doped Mg₂Si." Materials Science Forum 689 (June 2011): 102–7. http://dx.doi.org/10.4028/www.scientific.net/msf.689.102.

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The formation energy, structure relaxation and electronic structure of Mg2Si and Y-doped Mg2Si are investigated using first-principle calculations based the density functional theory. The general gradient approximation was used to treat the exchange and correlation potential. The calculated electronic structure shows that Mg2Si is a semiconductor with a direct gap of 0.27eV at G point. The preferential substitution site of Y inside Mg2Si is determined to be Mg. Y-doping makes the Si atoms around the impurity outward relaxation and increases the Seebeck coefficient, electrical conductivity and thermal conductivity of Mg2Si crystals simultaneously.

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Liu, Niu Can, Jun Qing Li, and Hai Dong Li. "Influence of Sb on Wear Resistance of In Situ Mg₂Si/Al-Si Composites." Advanced Materials Research 311-313 (August 2011): 197–200. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.197.

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The microstructure and wear resistance of in-situ Mg2Si/Al-Si were studied in the different content of Sb. The result shows that when the content of Sb is 0.4%, the refining effect of primary Mg2Si granules in Mg2Si/Al-Si composite is best. The shape of Mg2Si turned into fine and even granules compared to the shape of Chinese character or treelike crystal before modification. At the same, the composite shows the best wear resistance and the loss of wear quality was reduced by 19%～37%. The improvement of the wear resistance by alloy elements is related to the modification of the Mg2Si granules and enhancement of the matrix. The main wear mechanism of in-situ Mg2Si/Al-Si composite is grain-abrasion.

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Kim, Byungjoo, Jihoon Hwang, Yongho Park, and Youngcheol Lee. "Microstructural Improvement of Eutectic Al + Mg2Si Phases on Al–Zn–Si–Mg Cast Alloy with TiB2 Particles Additions." Materials 14, no. 11 (May 28, 2021): 2902. http://dx.doi.org/10.3390/ma14112902.

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In this study, the effects of adding TiB2 particles to eutectic Al + Mg2Si phases in aluminum alloys were analyzed. The eutectic Al + Mg2Si phases were modified effectively when a large amount of TiB2 was added, and changes in the shape, size, and distribution of the eutectic Al + Mg2Si phases were confirmed using a polarizing microscope and FE-SEM. The crystal structure of the TiB2 particles and Mg2Si phases were analyzed using HR-TEM, and the analysis confirmed that the TiB2 particles can act as heterogeneous nucleation sites. This paper intends to clarify the principle of phase modification of the eutectic Al + Mg2Si phases by TiB2 particles and proposes a new mechanism to improve Mg2Si phase modification when TiB2 particles are added.

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Liu, Yong Tian, Xian Tong, Ji Xing Lin, Li Yuan Niu, and Guang Yu Li. "The Influences of Holmium on Microstructure and Properties of In Situ Mg₂Si/Al Composites." Advanced Materials Research 900 (February 2014): 154–59. http://dx.doi.org/10.4028/www.scientific.net/amr.900.154.

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In this study, Mg2Si in in-situ Mg2Si/Al composites were subjected to modification treatment using rare earth element Holmium (Ho). The phase composition and microstructure before and after modification of Mg2Si were also analyzed using X-ray diffraction (XRD) and optical microscope (OM); in addition, its mechanical properties were detected as well. The results showed that moderate addition of rare earth element Ho in in-situ Mg2Si/Al composites presents good modification effects on Mg2Si, the morphology of primary Mg2Si was changed from cross shape before modification to dispersed irregular mass; optimal modification effect was obtained when 0.4% rare earth element Ho was added. Under this condition, the average size of primary Mg2Si was decreased from 74 μm before modification to 16 μm; its mechanical properties were promoted significantly; and its tensile strength increased from 134 MPa before modification to 174.6 MPa, its brinell hardness elevated from 76 HB to 90 HB.

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Wang, Dong Tao, Hai Tao Zhang, Ke Qin, Xing Han, Bo Shao, Ke Sheng Zuo, and Jian Zhong Cui. "Effect of Direct Chill Casting Speed and Heat Treatment on Microstructure and Mechanical Properties of Al-13.9%Mg₂Si Composite." Materials Science Forum 877 (November 2016): 15–19. http://dx.doi.org/10.4028/www.scientific.net/msf.877.15.

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The aim of this work is to investigate the effect of different casting speed in DC casting process and solution heat treatment of in situ Al-13.9%Mg2Si composite. The increasing of DC casting speed not only makes primary Mg2Si distribute more uniform and restricts segregation of primary Mg2Si particles, but also it reduces primary Mg2Si particle size. The DC casting speed significantly alter the eutectic Mg2Si phase from fibrous to fine dot-like and eutectic phase refines effectively. The results obtained from mechanical testing demonstrated that the increasing of DC casting speed intensifies both hardness and tensile strength values. Then, the billet were subjected to solutionizing at 500oC for holding time of 4h followed by quenching. The results indicate that the morphology of both primary and eutectic Mg2Si changes after heat treatment. Solutionizing leads to the dissolution of the Mg2Si particles and changes morphology from sharp edges to round shape. After solution heat treatment, tensile strength and elongation increase to 238.8MPa and 13.5%.

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Modak, A. R., David J. Smith, Z. G. Li, P. Boher, and Ph Houdy. "HREM Observations of Mg2Si-Based Multilayers for Soft X-Ray Optics." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 906–7. http://dx.doi.org/10.1017/s0424820100088841.

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Multilayers fabricated with alternating materials having significant differences in X-ray scattering powers are being investigated for applications in soft X-ray optics. Multilayers consisting of combinations of W, Rh, Fe, Si3N4, SiO2 and Si, C, B4C have been studied in the past. Mg2Si based multilayer structures are theoretically efficient reflectors of wavelengths above the Mg-Kα line (9.89 Å) and the Mg-Lα line (251.5 Å) because of their low absorption in the respective wavelength regimes due to the presence of magnesium. In the present study, Mg2Si based multilayers fabricated on silicon substrates by ultra high vacuum rf sputtering have been characterized by HREM. W, Si, and Mg2Si targets in conjunction with the introduction of nitrogen were employed to deposit alternate Mg2Si and W or Si3N4 layers. We report here our preliminary observations of a characteristic short period W/Mg2Si layered structure used above the Mg-Kα line and two long period multilayers based on W/Mg2Si and Si3N4/Mg2Si used above the Mg-Lα line.

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Xiao, Qing Quan, Quan Xie, Ke Jie Zhao, and Zhi Qiang Yu. "Effect of Sputtering Pressure on the Formation of Semiconducting Mg₂Si Films." Materials Science Forum 663-665 (November 2010): 166–69. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.166.

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Semiconducting Mg2Si films were fabricated on Si (111) substrates by magnetron sputtering and subsequent annealing, and the effects of sputtering pressure on the Mg2Si film growth were studied. The structural and morphological properties of Mg2Si films were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the Mg2Si (220) main diffraction peak intensity increased and then decreased with the increasing of sputtering pressure. The (220) diffraction peak got its maximum at 3.0 Pa sputtering pressure. The intensity of Mg2Si (200) and (400) diffraction peaks increased rapidly as the sputtering pressure decreased when the pressure was lower than 1.5 Pa. The films prepared at higher sputtering pressure had very irregular microstructures, and the surface of semiconducting Mg2Si films became smoother with the decreasing of the sputtering pressure.

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Itoh, Takashi, and Akira Tominaga. "Thermoelectric Properties of Al-doped Mg2Si Compounds Prepared via Three Kinds of Process for Grain Refinement." MRS Advances 1, no. 60 (2016): 3989–95. http://dx.doi.org/10.1557/adv.2016.374.

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ABSTRACTDimagnesium silicide is an eco-friendly thermoelectric compound whose constituent elements of both Mg and Si are non-toxic and exist in abundance on the earth. In this study, we attempted to control the thermal conductivity of Al-doped Mg2Si by grain refinement. Three types of Si powders, i.e., commercial coarse powder, its pulverized powder and commercial fine powder were prepared for synthesizing the Al-doped Mg2Si. Mg powder and one of the Si powders were weighed with Mg/Si mole ratio of 67/33, and mixed with Al powder with amount of 0.1 at.%. The Al-doped Mg2Si compounds were synthesized using three different Si powders via a liquid-solid phase reaction process under unified synthesizing conditions. A part of the synthesized Mg2Si powder using the coarse Si powder was pulverized. Four kinds of Mg2Si powders were sintered by pulse discharge sintering method under unified sintering conditions. The sintered samples of the synthesized Mg2Si powders made from the fine and the milled Si powders and of the milled Mg2Si powder had the grain-refined microstructure. Especially, the sintered sample of the milled Mg2Si powder was effective for grain refinement and for reduction of thermal conductivity, and had the best thermoelectric performance of ZT = 1.15 at 873 K.

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Kim, Yu-Mi, Se-Weon Choi, Young-Chan Kim, Chang-Seok Kang, and Sung-kil Hong. "Influence of the Precipitation of Secondary Phase on the Thermal Diffusivity Change of Al-Mg2Si Alloys." Applied Sciences 8, no. 11 (October 24, 2018): 2039. http://dx.doi.org/10.3390/app8112039.

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Al-Si-Mg alloys are investigated to determine the relationship between changes in the thermal diffusivity and precipitation behavior of the Mg2Si phase with various contents of Mg2Si and aging treatment conditions. The samples were solid solution-treated and then quenched with water (80 °C). Aging treatments were implemented at temperatures ranging from 180 to 240 °C for 5 h. The precipitation behavior of Mg2Si was observed using a heat flow curve using differential scanning calorimetry analysis. The thermal diffusivity of Al-Mg2Si alloy was affected by the precipitation of the Mg2Si phase, particularly in the meta-stable β phase. In the temperature range of precipitation occurrence, the thermal diffusivity of the alloy increased with the temperature when the precipitation of the meta-stable β phase of the sample was incomplete. However, at the same temperature, the samples in which precipitation had completed did not have any increased thermal diffusivity. The thermal diffusivity of the samples decreased when the meta-stable Mg2Si phase had dissolved in the matrix. The precipitation and dissolution of Mg2Si mainly affected the variation of thermal diffusivity in Al-Si-Mg. In contrast, the stable Mg2Si phase was not affected by changes in thermal diffusivity at a high temperature.

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Nordin, Nur Azmah, Tuty Asma Abu Bakar, Esah Hamzah, Saeed Farahany, and Ali Ourdjini. "Characterization of Phase Formation in Al-20%Mg₂Si-2%Cu Metal Matrix Composite." Solid State Phenomena 264 (September 2017): 186–89. http://dx.doi.org/10.4028/www.scientific.net/ssp.264.186.

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Advantage of Al-Mg2Si metal matrix composite (MMC) is due to the particulate reinforced Mg2Si in the Al matrix that has improved mechanical properties of the in situ composite. In particular, the composite has been chosen as the structural material for automotive and aerospace components. The hypereutectic Al-Mg2Si composite should be comprised of two morphologies, namely primary Mg2Si and pseudo-eutectic Al-Mg2Si phase. However, as-received commercial Al-20Mg2Si-2Cu in situ composite contained a wide range of elements that affect the resultant microstructure of the in situ composite. In fact, four different morphologies have been identified in the in situ composites. The first phase is dark facet primary Mg2Si particles, surrounded by pseudo-eutectic Al-Mg2Si phase in lamellar structure. Along the eutectic boundary is the formation of needle-like Al5FeSi intermetallic and the phase is surrounded by Al5Mg8Si6Cu2+Al2Cu as last phase nucleated. Optical micrograph, SEM imaging, EDX analysis and elemental mapping have revealed these phases correspond to shape of morphologies and respective molecular compound.

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Yang, Lu, Qing Hua Wang, Jie Li, Yuan Liu, and An Guo Huang. "Reaction Kinetics of Mg₂Si in the Laser Welding Pool of Aluminum Alloys." Advanced Materials Research 813 (September 2013): 55–63. http://dx.doi.org/10.4028/www.scientific.net/amr.813.55.

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The metallurgy reactions in the weld pool were analyzed with the application of reaction kinetics. Furthermore a formula to quantificationally calculate the amount of Mg2Si was generated. By means of calculating the thermodynamic condition of the reaction and combined with the verification testing, this article indicates that the metallurgical product Mg2Si was created in the liquid weld pool but not separated out from the arborescent crystal during its solid state. This thesis summarizes the precipitation mechanism of Mg2Si and explains the configuration, amount and location where Mg2Si was separated out by analyzing the phase diagrams and constitution diagrams. Relevant data suggests that: the content of Mg2Si is slightly less than Mg.

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Hernandez, Gustavo Castillo, Mohammad Yasseri, Sahar Ayachi, Johannes de Boor, and Eckhard Müller. "Hardness and Fracture Toughness of Solid Solutions of Mg2Si and Mg2Sn." Semiconductors 53, no. 13 (December 2019): 1831–37. http://dx.doi.org/10.1134/s1063782619130098.

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Zhang, Qiang, Qiangbing Lu, Yonggao Yan, Xianli Su, and Xinfeng Tang. "Ultrafast Synthesis and Related Phase Evolution of Mg2Si and Mg2Sn Compounds." Journal of Electronic Materials 46, no. 5 (February 17, 2017): 3172–81. http://dx.doi.org/10.1007/s11664-017-5325-z.

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Aizawa, Tatsuhiko, and Renbo Song. "Mechanically induced reaction for solid-state synthesis of Mg2Si and Mg2Sn." Intermetallics 14, no. 4 (April 2006): 382–91. http://dx.doi.org/10.1016/j.intermet.2005.07.003.

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37

Ajith Kumar, Kumaraswamy Kaliamma, Uma Thanu Subramonia Pillai, Bellambettu Chandrasekhara Pai, and Madhusudan Chakraborty. "Tribological Behavior of Mg-Mg₂Si In Situ Composite." Materials Science Forum 710 (January 2012): 401–6. http://dx.doi.org/10.4028/www.scientific.net/msf.710.401.

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Mg-Mg2Si in-situ composites by the addition of Si in Mg have become more attractive since the Mg2Si phase impedes the grain boundary sliding at elevated temperature because of its inherent properties which greatly improve the heat and wear resistances. In the present work, Mg-Mg2Si composites have been prepared by the liquid state processing with different amount of silicon additions. The microstructure and dry sliding tribological behavior of the composites have been studied. SEM studies reveal the wear mechanisms involved in these composites. The results indicate that wear rate of the composites is a function of Mg2Si content in the composite. The effect of Mg2Si morphology and distribution on the overall mechanism is also discussed.

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38

Yang, Mei Jun, Wei Jun Luo, Qiang Shen, Hong Yi Jiang, and Lian Meng Zhang. "Preparation and Thermoelectric Properties of Bi-Doped Mg₂Si Nanocomposites." Advanced Materials Research 66 (April 2009): 17–20. http://dx.doi.org/10.4028/www.scientific.net/amr.66.17.

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Nanocomposites and heavy doping both are regarded as effective way to improve materials’ thermoelectric properties. 0.7at% Bi-doped Mg2Si nanocomposites were prepared by spark plasma sintering. Results of thermoelectric properties tests show that the doping of Bi atom effectively improves the electrical conductivity of Mg2Si，and the nanocomposite structures are helpful to reduce thermal conductivity and increase Seebeck coefficient, hence improving the thermoelectric performance. A maximum dimensionless figure of merit of 0.8 is obtained for the Bi-doped Mg2Si nanocomposite with 50 wt % nanopowder inclusions at 823K, about 63% higher than that of Bi-doped Mg2Si sample without nanopowder inclusions and 119% higher than that of microsized Mg2Si sample without Bi-doped, respectively.

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39

Si, Yi, and D. S. Kevluzov. "Research on the Long-Lasting and Remelting Properties of Nd Modification Effect on Cast Al-Mg₂Si Metal Matrix Composite." Materials Science Forum 1001 (July 2020): 196–201. http://dx.doi.org/10.4028/www.scientific.net/msf.1001.196.

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The cast Al-Mg2Si metal matrix composite was prepared by metal model casting process with rare earth element Nd as the modificator. The effects of modification duration and remelting times on microstructure and mechanical properties of the composite were investicated by optical microscope (OM) and electronic universal testing machine. The results show that, after introducing a proper amount of Nd, both primary and eutectic Mg2Si in the Al-18 wt.%Mg2Si composite were well modified. The morphology of primary Mg2Si is changed from irregular or dendritic to polyhedral shape and the morphology of the eutectic Mg2Si phase is altered from flake-like to very short fibrous or dot-like. Moreover, the effect is of long-lasting and remelting properties. After the composite is modified for 300 min and remelted by 6 times, its primary and eutectic Mg2Si structures are still in modification state of small block and slices, and the tensile properties of the composite are not significantly affected.

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Ghandvar, Hamidreza, Mostafa Abbas Jabbar, Seyed Saeid Rahimian Koloor, Michal Petrů, Abdollah Bahador, Tuty Asma Abu Bakar, and Katsuyoshi Kondoh. "Role B4C Addition on Microstructure, Mechanical, and Wear Characteristics of Al-20%Mg2Si Hybrid Metal Matrix Composite." Applied Sciences 11, no. 7 (March 29, 2021): 3047. http://dx.doi.org/10.3390/app11073047.

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In the current study, the effect of different B4C additions (0, 2.5, 5, and 10 wt%) on the microstructural, solidification behavior, mechanical, and tribological properties of Al-20%Mg2Si composite were studied by means of scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Vickers hardness, tensile, and dry sliding wear tests. The cooling curve thermal analysis (CCTA) approach was utilized to monitor the influence of B4C particles on the solidification behavior of Al-20%Mg2Si composite. The results revealed that the addition of B4C particles up to 10 wt% reduced the nucleation temperature (TN) and growth temperature (TG) of the primary Mg2Si phase. Moreover, the proper amount of B4C added to Al-20%Mg2Si composite has a significant effect on the microstructural alteration, mechanical, and tribological properties of the composite. The mean size of primary Mg2Si in Al-Mg2Si composite was 47 μm, in which with the addition of 5 wt% B4C, the particle size decreased to 33 μm. The highest UTS (217 MPa) and El% (7%) was achieved in Al-20%Mg2Si-5%B4C hybrid composite. The cast Al-20%Mg2Si composite revealed the brittle mode of fracture with some cleavage characterization, in which with the addition of 5%B4C, the fracture mode altered to a more ductile fracture. The wear results revealed that the Al-20%Mg2Si-5%B4C hybrid composite has the highest wear resistance with the lowest wear rate (0.46 mm3/Km) and friction coefficient (µ = 0.52) under 20 N applied load compared to other fabricated composites with mild abrasion as the governed wear mechanism.

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Yu, Hong, Shentong Ji, Xiangyan Luo, and Quan Xie. "Technology CAD (TCAD) Simulations of Mg2Si/Si Heterojunction Photodetector Based on the Thickness Effect." Sensors 21, no. 16 (August 18, 2021): 5559. http://dx.doi.org/10.3390/s21165559.

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Research on infrared detectors has been widely reported in the literature. For infrared detectors, PbS, InGaAs, PbSe, InSb, and HgxCd1-xTe materials are the most widely used and have been explored for photodetection applications. However, these are toxic and harmful substances which are not conducive to the sustainable development of infrared detectors and are not eco-friendly. Mg2Si is a green, healthy, and sustainable semiconductor material that has the potential to replace these toxic and damaging photoelectric materials, making photoelectric detectors (PDs) green, healthy, and sustainable. In this work, we report on the results of our simulation studies on the PN junction Mg2Si/Si heterojunction PD. A model structure of Mg2Si/Si heterojunction PD has been built. The effects of Mg2Si and Si layer thickness on the optical and electrical performance of Mg2Si/Si heterojunction PD are discussed. For the purpose of this analysis, we consider electrical performance parameters such as I–V curve, external quantum efficiency (EQE), responsivity, noise equivalent power (NEP), detectivity, on-off ratio, response time, and recovery time. The simulation results show that the Mg2Si/Si heterojunction PD shows optimum performance when the thickness of Si and Mg2Si layers are 300 nm and 280 nm, respectively. For the optimized structure, the reverse breakdown voltage was found to be −23.61 V, the forward conduction voltage was 0.51 V, the dark current was 5.58 × 10−13 A, and the EQE was 88.98%. The responsivity was found to be 0.437 A/W, the NEP was 6.38 × 10−12 WHz1/2, and the detectivity was 1.567 × 1011 Jones. With the on-off ratio of 1566, the response time was found to be 0.76 ns and the recovery time was 5.75 ns. The EQE and responsivity peak wavelength of PD show a redshift as the thickness of Mg2Si increases. The Mg2Si heterojunction PD can effectively detect infrared light in the wavelength range of 400 to 1400 nm. The simulation results can be utilized to drive the development of green Mg2Si/Si heterojunction PD in the future.

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Meng, Qing Sen, L. Q. Wang, B. S. Li, L. Z. Ding, and Shao Ping Chen. "Thermoelectric Properties of Y-Doped Mg₂Si Prepared by Field-Activated and Pressure-Assisted Reactive Sintering." Advanced Materials Research 79-82 (August 2009): 1639–42. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1639.

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Reactive sintering of elemental powders was used to form Y-doped Mg2Si (Y: 1000, 2000, 3000ppm) using a field-activated pressure assisted synthesis (FAPAS) method. XRD analysis, and the calculation of lattice constant (a) indicates that 1000ppm is the solid solubility of Y in Mg2Si. Sample doped with 2000ppm Y owns better performances, the absolute value of Seebeck Coefficient increases in the temperature of 288-580K and is higher than that of non-doped Mg2Si, and it got higher electric conductivity and higher power factor, which reaches up to 1.67 times of non-doped Mg2Si at 438K and 2.03 times of that of non-doped Mg2Si at about 408K. Meanwhile, the introduction of Y can decrease thermo-conductivity obviously, proving that the introduction of Y is favorable for both electrical and thermal properties.

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Braszczyńska-Malik, Katarzyna N., and Marcin A. Malik. "Microstructure and Mechanical Properties of Hypo- and Hypereutectic Cast Mg/Mg2Si Composites." Materials 13, no. 16 (August 14, 2020): 3591. http://dx.doi.org/10.3390/ma13163591.

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In this paper, the microstructure and mechanical properties of two magnesium matrix composites—a hypoeutectic with 1.9 wt% Mg2Si phase and a hypereutectic with 19 wt% Mg2Si compound—were analyzed. The investigated materials were prepared using the gravity casting method. Microstructure analyses of the fabricated composites were carried out by XRD and light microscopy. The tensile and compression strength as well as yield strength of the composites were examined in both uniaxial tensile and compression tests. The microstructure of the hypoeutectic composite was in agreement with the phase diagram and composed of primary Mg dendrites and an Mg–Mg2Si eutectic mixture. For the hypereutectic composite, besides the primary Mg2Si phase and eutectic mixture, additional magnesium dendrites surrounding the Mg2Si compound were observed due to nonequilibrium solidification conditions. The composites exhibited a rise in the examined mechanical properties with an increase in the Mg2Si weight fraction and also a higher tensile and compression strength in comparison to the pure magnesium matrix (cast in the same conditions). Additionally, analyses of fracture surfaces of the composites carried out using scanning electron microscopy (SEM + EDX) are presented.

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44

Moharami, A., A. Razaghian, B. Babaei, OO Ojo, and M. Šlapáková. "Role of Mg2Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg2Si composite." Journal of Composite Materials 54, no. 26 (May 19, 2020): 4035–57. http://dx.doi.org/10.1177/0021998320925528.

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This paper investigates the effect of different tool pin morphologies on the inter-mixing capability, microstructure, mechanical properties, corrosion, fracture, and wear behaviors of the dissimilar friction stir welded AA6061-T6 alloy--Al 20wt% Mg2Si composite. Grooved shoulder tools with varying pin profiles such as tapered cylindrical, threaded tapered cylindrical, and triangular tapered pins were used for joining the base materials. The parameter combination of 80 mm/min travel speed and 1000 r/min rotation speed (at which no visible flow-induced defect was obtained) was used for this study. Among the pin profiles, the triangular tapered pin produced significantly improved intermingling/inter-material flow, fragmentation, and dispersion of the primary Mg2Si particles in the AA6061-T6/Al-Mg2Si joint. The triangular tapered tool reduced the average grain sizes of the AA6061 alloy and the Mg2Si particles from 18.4 to 4.6 µm and from 115 to 7.5 µm, respectively. Intermetallic phases of Mg2Si, AlFe, Al3.21Si0.47, and Al0.7Fe3Si0.3 are formed in the weld nugget of all the AA6061/Al-Mg2Si joints. The tensile strengths of the joints fabricated with tapered cylindrical, threaded tapered cylindrical, and triangular tapered tools are 108, 139, and 141 MPa, respectively. Abrasive wear is promoted in the joints fabricated with triangular tapered tool due to the homogeneous dispersion and fragmentation of the inherent hard Mg2Si particles. The corrosion attack is dependent on the fragmentation level of the Mg2Si phase. Triangular tapered pin tool is recommended for dissimilar Al/composite welding due to favorable tool-induced material flow, dispersion, and fragmentation of reinforcement.

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Oginuma, Hideki, Katsuyoshi Kondoh, Takashi Yamaguchi, and Eiji Yuasa. "Solid-State Synthesis of Magnesium Silicide via Repeated Plastic Working and Spark Plasma Sintering." Materials Science Forum 475-479 (January 2005): 2895–98. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.2895.

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In this study, the solid-state reaction to form Mg2Si bulky materials via spark plasma sintering (SPS) process was discussed. Elemental powder mixture of Mg-33.33mol%Si was refined and consolidated as green compacts by repeated plastic working (RPW) SPS was performed to synthesize and sinter magnesium silicide at 1100K from the RPWed compact. The only peaks of Mg2Si, not Mg and Si, were detected by X-ray diffraction analysis. Mg2Si bulky intermetallic began to shrink above 800K during SPS process, and its densification significantly occurred. The density of SPSed Mg2Si bulk material is about 100% of the theoretically relative one.

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46

Si, Yi. "Effect of Pr Modification Treatment on the Microstructure and Mechanical Properties of Cast Al-Mg₂Si Metal Matrix Composite." Advanced Materials Research 936 (June 2014): 23–27. http://dx.doi.org/10.4028/www.scientific.net/amr.936.23.

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The effect of different concentrations of Pr on the microstructure and tensile properties of cast Al-18 wt.%Mg2Si in situ metal matrix composite was investigated. The results show that the addition of proper amount of Pr has significant modification effect on primary Mg2Si in the Al-18 wt.% Mg2Si composite. With the increase of Pr content from 0.1 to 0.7%, the morphology of primary Mg2Si is changed from irregular or dendritic to polyhedral shape, and its average particle size is significantly decreased from 65 to 17 μm. When the Pr content exceeds 1.0%, the primary Mg2Si become coarse again. Tensile tests reveal that the Pr addition improves the tensile strength and ductility of the material. Comparing with those of unmodified composite, the ultimate tensile strength and percentage elongation with 0.7% Pr are increased by 36.5% and 161.6%, respectively.

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Itoh, Takashi, and Takumi Nakano. "Optimization of Degreasing-Sintering Process for Mg2Si/PLA Mixture and Influences of Additive Amount of Al on Sintered Density and Thermoelectric Performance of Mg2Si Fabricated by the Optimized Process." MRS Advances 5, no. 10 (2020): 459–67. http://dx.doi.org/10.1557/adv.2020.87.

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ABSTRACTFused deposition modelling (FDM) type of 3D printing is widely used for manufacturing complex shaped polymer products. Recently, the metal/polymer composite products can be made by 3D printer using metal/polymer composite filament. Now, we are planning to develop a new manufacturing process of the thermoelectric (TE) elements or modules by combining the FDM-type 3D printing and the degreasing-sintering process. In this work, we focused on the degreasing-sintering process of the mixture of Mg2Si and polylactic acid (PLA) powders. Mg2Si compound powder was synthesized by a liquid-solid phase reaction (LSPR) method. The powder mixtures of Mg2Si, Al and PLA were pressed and heated in a pulse discharge sintering (PDS) chamber under a vacuum in various degreasing conditions. Following the degreasing, the sintering of Mg2Si was carried out in the same PDS chamber at various starting sintering temperatures. Sintered density, Seebeck coefficient and electrical resistivity of the consolidated Mg2Si were measured and the power factor as a TE performance was estimated from the TE properties. The optimum conditions of degreasing-sintering process maximizing the sintered density and the TE performance of Al-doped Mg2Si were investigated. Furthermore, the influences of the additive amount of Al on the sintered density and the TE performance of Mg2Si fabricated via the optimized degreasing-sintering process were investigated.

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48

Luo, Xiao Dong, Hao Liu, Wen Lin Xu, and Yong Xiang Zhu. "Progress on Mg₂Si Thermoelectric Materials." Advanced Materials Research 886 (January 2014): 71–74. http://dx.doi.org/10.4028/www.scientific.net/amr.886.71.

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Mg2Si which is composed of less toxic and naturally abundant elements,has attracted more attention for its potential application to thermoelectric devices. In this paper, the basic performance and preparation technique of Mg2Si thermoelectric materials are introduced. reviewed the current research progress of Mg2Si thermoelectricity. And the paper points out the existing problems and the trend of study in the future.

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Liu, Niu Can, Guang Sheng Kang, and Zhong Xia Liu. "Study on Microstructure and Impact Toughness of In Situ Mg₂Si Particle Reinforced Al-Si Matrix Composites." Advanced Materials Research 557-559 (July 2012): 215–18. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.215.

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The microstructure and impact toughness of in-situ Mg2Si/Al-Si composites were studied in the different content of Sb. The results show that Sb can improve the microstructure and impact toughness of Mg2Si/Al-Si composites. When the content of Sb is 0.4%, the morphology of primary Mg2Si changes from dendrites to fine particles, the average size of Mg2Si particles is refined from 52μm to 25μm, and the impact toughness of the composites increases from 6.3572J/cm2 to 11.4394J/cm2. The improvement of impact toughness can be attributed to the fine-grain strengthening. However, excessive Sb is disadvantageous to the modification of the composites.

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Wang, Mingjie, Guowei Zhang, Hong Xu, and Yizheng Fu. "Investigation on Mg3Sb2/Mg2Si Heterogeneous Nucleation Interface Using Density Functional Theory." Materials 13, no. 7 (April 3, 2020): 1681. http://dx.doi.org/10.3390/ma13071681.

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In this study, the cohesive energy, interfacial energy, electronic structure, and bonding of Mg2Si (111)/Mg3Sb2 (0001) were investigated by using the first-principles method based on density functional theory. Meanwhile, the mechanism of the Mg3Sb2 heterogeneous nucleation potency on Mg2Si grains was revealed. The results indicated that the Mg3Sb2 (0001) slab and the Mg2Si (111) slab achieved bulk-like characteristics when the atomic layers N ≥ 11, and the work of adhesion of the hollow-site (HCP) stacking structure (the interfacial Sb atom located on top of the Si atom in the second layer of Mg2Si) was larger than that of the other stacking structures. For the four HCP stacking structures, the Sb-terminated Mg3Sb2/Si-terminated Mg2Si interface with a hollow site showed the largest work of adhesion and the smallest interfacial energy, which implied the strongest stability among 12 different interface models. In addition, the difference in the charge density and the partial density of states indicated that the electronic structure of the Si-HCP-Sb interface presented a strong covalent, and the bonding of the Si-HCP-Mg interface and the Mg-HCP-Sb interface was a mixture of a covalent bond and a metallic bond, while the Mg-HCP-Mg interfacial bonding corresponded to metallicity. As a result, the Mg2Si was conducive to form a nucleus on the Sb-terminated-hollow-site Mg3Sb2 (0001) surface, and the Mg3Sb2 particles promoted the Mg2Si heterogeneous nucleation, which was consistent with the experimental expectations.

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Journal articles on the topic 'Mg2Si'

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