Effect of Sm content on microstructure and properties of extruded Mg-6Al-2Sr alloy

Abstract

In this paper, the strengthening mechanism of different Sm content on extruded Mg-6Al-2Sr alloy was studied. The microstructure was observed by metallographic experiment, X-ray diffraction, scanning electron microscopy and transmission electron microscopy, and the effect of Sm content on the microstructure of the alloy was analyzed by EBSD. The main experiment in this paper is the extrusion experiment of Mg-6Al-2Sr cast alloy with different Sm content. The results show that with the increase of Sm content, the generated Al₂Sm phase is broken under the action of extrusion, and uniformly dispersed at the grain boundary along the extrusion direction, which hinders the grain growth. However, with the increase of Sm content, the Al₂Sm phase increases and aggregates at the grain boundary, which has an adverse effect on the mechanical properties of the alloy. When the Sm content is 1.5 wt%, the average grain size of the alloy is the finest, and its tensile strength, yield strength and elongation reach 297.9 MPa, 257.8 MPa and 21.3%, respectively. The hardness reaches HV78.9, which is 15.6% higher than that of the alloy with 0 wt% Sm content. The yield strength increased by 34.6% and the elongation increased by 34.8%.

Keywords

Mg-6Al-2Sr-xSm alloy / microstructure / electron backscattered diffraction (EBSD) / mechanical properties

References

[[1]] Yang G-Q, Peng X-D, Yang Y, et al.. Microstructure and mechanical properties of as-cast and extruded Mg−8Li−3Al−0.7Si alloy [J]. Journal of Central South University, 2018, 25(4): 764-771,

[[2]] Chen X-Y, Li Q-A, Zhu L-M, et al.. Effect of Sm on microstructure, mechanical property and lattice constant of as-cast Mg−11Gd−2Y−0.6Al alloy [J]. Transactions of the Indian Institute of Metals, 2019, 72(7): 1783-1789,

[[3]] Yao Y-T, Chen L-Q, Wang W-B. Influence of B₄C particle size on microstructure and damping capacities of (B₄C+Ti)/Mg composites [J]. Journal of Central South University, 2021, 28: 648-656,

[[4]] Liu W-H, Bao J-X, Qiao M-L, et al.. Microstructures and mechanical properties of Mg−6Zn−1Y−0.85Zr alloy prepared at different extrusion temperatures and speeds [J]. Journal of Materials Research and Technology, 2022, 21: 1042-1052,

[[5]] Xing S-W, Li C-X, Li C, et al.. Effect of Sm content on microstructure evolution and mechanical properties of as-cast Mg − 6Al − 2Sr alloys [J]. Journal of Central South University, 2022, 29(12): 3811-3824,

[[6]] Ma T, Zhao S-C, Wang L-P, et al.. Influence of solution treatment time on precipitation behavior and mechanical properties of Mg−2.0Nd−2.0Sm−0.4Zn−0.4Zr alloy [J]. Materials, 2021, 14(17): 5037, pmcid: 8433664

[[7]] Liu J-A, Yang C-X, Yang M-L. The microstructure and mechanical properties of die-cast Mg−6Al−2Sm−xCu alloys [J]. Metals, 2017, 7(5): 164,

[[8]] Guan K, Egusa D, Abe E, et al.. Microstructures and mechanical properties of as-cast Mg−Sm−Zn−Zr alloys with varying Gd contents [J]. Journal of Magnesium and Alloys, 2022, 10(5): 1220-1234,

[[9]] Liu Z-H, Wang L, Wang L-P, et al.. Effect of Al addition on the grain refinement and mechanical properties of as-cast Mg−5Y−4Sm alloys [J]. Journal of Materials Science, 2022, 57(31): 15137-15150,

[[10]] Chen Y-H, Wang L-P, Feng Y-C, et al.. Effect of Ca and Sm combined addition on the microstructure and elevated-temperature mechanical properties of Mg−6Al alloys [J]. Journal of Materials Engineering and Performance, 2019, 28(5): 2892-2902,

[[11]] Gui Y-W, Li Q-A, Chen J. Effects of Sm content on microstructures and mechanical properties of casting Mg−Y−Nd−Sm−Zr alloys [J]. Materials Research Express, 2018, 5(7): 076515,

[[12]] QIN Jun-long, CHANG Li-li, SU Xiao-jing. Influence of Sr on microstructure evolution, mechanical and corrosion properties of extruded Mg−2Zn−0.5Ca alloy [J]. Journal of Magnesium and Alloys, 2023 DOI: https://doi.org/10.1016/j.jma.2023.03.008.

[[13]] Qin P-F, Yang Q, He Y-Y, et al.. Microstructure and mechanical properties of high-strength high-pressure die-cast Mg−4Al−3La−1Ca−0.3Mn alloy [J]. Rare Metals, 2021, 40(10): 2956-2963,

[[14]] Singh L K, Joseph P, Srinivasan A, et al.. Microstructure and mechanical properties of gadolinium- and misch metal-added Mg−Al alloy [J]. Rare Metals, 2022, 41(9): 3205-3213,

[[15]] Wang F, Sun S-J, Wang Z, et al.. Microstructure, mechanical properties and first-principle analysis of vacuum die-cast Mg−7Al alloy with Sn addition [J]. Rare Metals, 2022, 41(6): 1961-1967,

[[16]] Zhao T-S, Hu Y-B, Pan F-S, et al.. Effect of Zn content on the microstructure and mechanical properties of Mg−Al−Sn−Mn alloys [J]. Materials, 2019, 12(19): 3102, pmcid: 6803948

[[17]] Liu Y F, Jia X J, Qiao X G, et al.. Effect of La content on microstructure, thermal conductivity and mechanical properties of Mg−4Al magnesium alloys [J]. Journal of Alloys and Compounds, 2019, 806: 71-78,

[[18]] Zhang X-J, Wang H-W, Ye F-B, et al.. Cooperative effect of Mg and Si contents on the microstructural evolution, mechanical performance, and deformation behavior of cast Al−Li−Mg−Si alloys [J]. Materials Science and Engineering A, 2022, 841: 142976,

[[19]] Emami S M, Divandari M, Hajjari E, et al.. Comparison between conventional and lost foam compound casting of Al/Mg light metals [J]. International Journal of Cast Metals Research, 2013, 26(1): 43-50,

[[20]] Wang C, Cui J, Luo T-J, et al.. Effect of Al on the microstructure and mechanical properties of Mg−6Zn−2Sn−0.5Mn alloy [J]. Materials Science and Technology, 2019, 35(12): 1464-1470,

[[21]] Fu Y-K, Wang L-P, Zhao S-C, et al.. Effect of Al content on microstructure evolution and mechanical properties of As-cast Mg−11Gd−2Y−1Zn alloy [J]. Materials, 2021, 14(23): 7145, pmcid: 8658446

[[22]] Nayeri T, Yari M, Sadreddini S. Effect of Sr on the microstructure and properties of Mg-6Al alloy [J]. Protection of Metals and Physical Chemistry of Surfaces, 2016, 52(2): 273-278,

[[23]] SARTIKA V D, TRINANDA A F, SYARIF R A, et al. The role of heat treatment on characteristics of Mg−Al−Sr reinforced nano-SiC composite [J]. IOP Conference Series: Materials Science and Engineering, 2019, 553. DOI: https://doi.org/10.1088/1757-899x/553/1/012027.

[[24]] Song J, Gao Y-H, Liu C-M, et al.. The effect of Sr addition on the microstructure and corrosion behaviour of a Mg−Zn−Ca alloy [J]. Surface and Coatings Technology, 2022, 437: 128328,

[[25]] Dargusch M S, Shi Z-M, Zhu H-L, et al.. Microstructure modification and corrosion resistance enhancement of die-cast Mg−Al−Re alloy by Sr alloying [J]. Journal of Magnesium and Alloys, 2021, 9(3): 950-963,

[[26]] L’Espérance G, Plamondon P, Kunst M, et al.. Characterization of intermetallics in Mg−Al−Sr AJ62 alloys [J]. Intermetallics, 2010, 18(1): 1-7,

[[27]] Afsharnaderi A, Lotfpour M, Mirzadeh H, et al.. Enhanced mechanical properties of as-cast AZ91 magnesium alloy by combined RE−Sr addition and hot extrusion [J]. Materials Science and Engineering A, 2020, 792: 139817,

[[28]] Zhu X-C. . Effect of alloying element Sb on microstructure and properties of Mg−5Al−2Sr alloy [D], 2012 Nanjing Nanjing University of Aeronautics and Astronautics (in Chinese)

[[29]] Kong L-H. Two main and a new type rare earth elements in Mg alloys: A review [J]. IOP Conference Series: Materials Science and Engineering, 2017, 242: 012026,

[[30]] Hu Y, Yu N, Zhao L-Z, et al.. Effect of Sm on the microstructure and properties of Mg−9Al alloy [J]. International Journal of Cast Metals Research, 2017, 30(6): 317-321,

[[31]] Feng J-K. . Study on the deformation law and microstructure evolution mechanism of semi-solid/rapid extrusion shear process of magnesium alloy [D], 2021 Chongqing Chongqing University (in Chinese)

[[32]] Zhang S-H, Song G-S, Xu Y, et al.. Application of schmid factor in Mg alloy deformation micromechanism investigation [J]. Journal of Netshape Forming Engineering, 2014, 6(6): 1-6 39, 161. (in Chinese)

[[33]] Guerza-Soualah F, Azzeddine H, Baudin T, et al.. Microstructural and textural investigation of an Mg−Dy alloy after hot plane strain compression [J]. Journal of Magnesium and Alloys, 2020, 8(4): 1198-1207,

[[34]] Ma C-H, Pan F-S, Lu Z-W. Uniaxial compressive properties and fracture analysis of Mg−9Al−5Sn−xSb extruded magnesium alloy [J]. Journal of Materials Heat Treatment, 2020, 41(9): 126-131

[[35]] Caldatto Dalan F, de Lima Andreani G F, et al.. Effect of ECAP processing on distribution of second phase particles, hardness and electrical conductivity of Cu−0.81Cr−0.07Zr alloy [J]. Transactions of Nonferrous Metals Society of China, 2022, 32(1): 217-232,

[[36]] Yu H-S. . Study on microstructure and properties of modified and deformed Mg−5Sn−1Si alloy [D], 2021 Zhengzhou Henan Polytechnic University (in Chinese)