激光选区熔化AlSi10Mg合金微观组织及力学性能研究
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摘要
AlSi10Mg合金具有良好的气密性,较好的流动性,热裂倾向小,收缩率小,强度高等优点,在汽车、航空航天等领域被广泛应用。随着零部件轻量化的需求增大,铝合金零件的结构和形状也愈发复杂,传统铸造技术已经无法满足市场需求。鉴于此,研究采用激光选区熔化技术快速凝固成形AlSi10Mg合金。利用激光选区熔化技术制备AlSi10Mg合金,主要分析了激光选区熔化后和不同温度时效处理后合金的显微组织、物相构成以及力学性能的变化。试验结果表明,激光选区熔化AlSi10Mg合金显微组织由基体区和热影响区组成,不同层之间的熔池呈椭圆形叠加分布,熔池宽约为250～300μm,深为100～200μm。时效处理后,由于Si原子的扩散,枝晶状态的共晶硅完全转变为颗粒状,且随着时效温度的升高,共晶硅的平均尺寸增加。时效处理前后,合金的物相均由Al基体相和Si相组成,但是时效后,由于过饱和Al(Si)固溶体的Si原子的析出,Al相的峰值向左偏移。激光选区熔化后合金具有最高的硬度值,时效处理后,硬度值急剧下降。随时时效温度的升高,硬度值降低。激光选区熔化技术能够有效细化AlSi10Mg合金的微观组织,并能显著提高合金的力学性能。
AlSi10 Mg alloy displays excellent properties, such as good air tightness, good fluidity, small thermal cracking tendency, small shrinkage and high strength. It is widely used in automotive, aerospace and other fields. With the increasing demand for lightweight components, the structure and shape of aluminum alloy parts become more complex, and traditional casting techniques is difficult to meet market demands. In view of this, the rapid solidification of AlSi10 Mg alloy by selective laser melting(SLM) was studied. The AlSi10 Mg alloy was prepared by selective laser melting(SLM) technique. The microstructure, phase composition and mechanical properties of the alloy after laser treatment and melting at different temperatures were analyzed. The experimental results show that the microstructure of the AlSi10 Mg alloy by selective laser melting consists of the matrix region and the heat-affected zone. The molten pool between the different layers are elliptically superposition. The width of the molten pool is about 250～300 μm, and the depth is about 100～200 μm. After the aging treatment, due to the diffusion of Si atoms, the eutectic silicon in the dendritic state is completely transformed into a granular shape, and as the aging temperature increases, the average size of the eutectic silicon increases. The phase of the alloy consist of Al matrix phase and Si phase before and after the aging treatment. However, after aging, the peak of the Al phase shifts to the left due to precipitation of Si atoms in the supersaturated Al(Si) solid solution. After the selective laser melting, the alloy has the highest hardness value, and the hardness value decreases sharply after the aging temperature. When the temperature rises at any time, the hardness value decreases. Selective laser melting technology can effectively refine the microstructure of AlSi10 Mg alloy and significantly improve the mechanical properties of the alloy.
AlSi10 Mg alloy displays excellent properties, such as good air tightness, good fluidity, small thermal cracking tendency, small shrinkage and high strength. It is widely used in automotive, aerospace and other fields. With the increasing demand for lightweight components, the structure and shape of aluminum alloy parts become more complex, and traditional casting techniques is difficult to meet market demands. In view of this, the rapid solidification of AlSi10 Mg alloy by selective laser melting(SLM) was studied. The AlSi10 Mg alloy was prepared by selective laser melting(SLM) technique. The microstructure, phase composition and mechanical properties of the alloy after laser treatment and melting at different temperatures were analyzed. The experimental results show that the microstructure of the AlSi10 Mg alloy by selective laser melting consists of the matrix region and the heat-affected zone. The molten pool between the different layers are elliptically superposition. The width of the molten pool is about 250～300 μm, and the depth is about 100～200 μm. After the aging treatment, due to the diffusion of Si atoms, the eutectic silicon in the dendritic state is completely transformed into a granular shape, and as the aging temperature increases, the average size of the eutectic silicon increases. The phase of the alloy consist of Al matrix phase and Si phase before and after the aging treatment. However, after aging, the peak of the Al phase shifts to the left due to precipitation of Si atoms in the supersaturated Al(Si) solid solution. After the selective laser melting, the alloy has the highest hardness value, and the hardness value decreases sharply after the aging temperature. When the temperature rises at any time, the hardness value decreases. Selective laser melting technology can effectively refine the microstructure of AlSi10 Mg alloy and significantly improve the mechanical properties of the alloy.
引文
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[15] WEI P,WEI Z Y,CHEN Z,et al.The AlSi10Mg samples produced by selective laser melting:single track,densification,microstructure and mechanical behavior[J].Applied Surface Science,2017(408):38-50.
[16] THIJS L,KEMPEN K,KRUTH J P,et al.Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder[J].Acta Material,2013(61):1809-1819.
[17] LASAGNI F,MINGLER B,DUMONT M,et al.Precipitation kinetics of Si in aluminium alloys[J].Materials Science Engineering:A,2008(480):383-391.
[18] WEI Z J,MA P,Wang H W,et al.The thermal expansion behaviour of SiCp/Al-20Si composites solidified under high pressures[J].Materials & Design,2015(65):387-394.
[2] CHEN H Y,GU D H,DAI D H,et al.A novel approach to direct preparation of complete lath martensite microstructure in tool steel by selective laser melting[J].Materials Letters,2018(227):128-131.
[3] 卢秉恒,李涤尘.增材制造(3D打印)技术发展[J].机械制造与自动化,2013(4):1-4.
[4] PRASHANTH K G,SCUDINO S,KLAUSS H J,et al.Microstructure and mechanical properties of Al-12Si produced by selective laser melting:Effect of heat treatment[J].Material Science Engineering:A,2013(590):153-160.
[5] MA P,PRASHANTH K G,SCUDINO S,et al.Influence of annealing on mechanical properties of Al-20Si processed by selective laser melting[J].Metals,2014(4):28-36.
[6] 史玉升,鲁中良,章文献,等.选择性激光熔化快速成形技术与装备[J].中国表面工程,2006,19(z1):150-153.
[7] 袁茂强,郭立杰,王永强,等.增材制造技术的应用及其发展[J].机床与液压,2016(5):183-188.
[8] WANG D Z,YU C F,MA J,et al.Densification and crack suppression in selective laser melting of pure molybdenum[J].Materials & Design,2017(129):44-52.
[9] ROMEI F,GRUBISIC A N,GIBBON D.Manufacturing of a high-temperature resistojet heat exchanger by selective laser melting[J].Acta Astronautica,2017(138):356-368.
[10] WU J,WANG X Q,WANG W,et al.Microstructure and strength of selectively laser melted AlSi10Mg[J].Acta Materialia,2016(117):311-320.
[11] BIROL Y.AlB3 master alloy to grain refine AlSi10Mg and AlSi12Cu aluminium foundry alloys[J].Journal of Alloys and Compounds,2012(513):150-153.
[12] 张文奇.AlSi10Mg合金粉末的选区激光熔化成形工艺及性能研究[D].武汉:华中科技大学,2015.
[13] 梁涛.亚共晶铝硅合金AlSi10Mg的压铸工艺研究[D].上海:上海交通大学,2012.
[14] TANG M,CHRIS PISTORIUS P.Oxides,porosity and fatigue performance of AlSi10Mg parts produced by selective laser melting[J].International Journal of Fatigue,2017(94):192-201.
[15] WEI P,WEI Z Y,CHEN Z,et al.The AlSi10Mg samples produced by selective laser melting:single track,densification,microstructure and mechanical behavior[J].Applied Surface Science,2017(408):38-50.
[16] THIJS L,KEMPEN K,KRUTH J P,et al.Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder[J].Acta Material,2013(61):1809-1819.
[17] LASAGNI F,MINGLER B,DUMONT M,et al.Precipitation kinetics of Si in aluminium alloys[J].Materials Science Engineering:A,2008(480):383-391.
[18] WEI Z J,MA P,Wang H W,et al.The thermal expansion behaviour of SiCp/Al-20Si composites solidified under high pressures[J].Materials & Design,2015(65):387-394.
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