热处理对选区激光熔化成形AlSi10Mg合金显微组织及力学性能的影响

摘要

AlSi10Mg alloy was prepared by selective laser melting(SLM)process,and then treated by annealing,solid solution and T6 treatment,respectively.The effects of heat treatment on microstructures and mechanical properties of AlSi10Mg alloy produced by SLM were investigated in order to improve heat treatment process of the alloy.The results show that the phases in as-built AlSi10Mg SLM products are α-Al matrix and eutectic Si.The eutectic structure [α-Al+Si] is continuous network distribution on the matrix of α-Al.The sections of both XOY and XOZ have coarse grain,fine crystal and heat affected zones.After annealing treatment,the eutectic Si network is partial dissolution and fracture,the strength decreases and the hardness increases slightly.While after T6 treatment,the eutectic Si appears with scattered and regular geometry inlays in the α-Al matrix,the tensile strength of the alloy decreases,yield strength slightly increases,and ductility significantly increases.In a comprehensive comparison with respect to strength and ductility,the T6 treatment is more suitable for the AlSi10Mg SLM products.%采用选区激光熔化成形法制备AlSi10Mg合金,然后分别进行退火、固溶以及T6处理,研究热处理工艺对合金显微组织与力学性能的影响,优化其热处理工艺.结果表明:选区激光熔化成形AlSi10Mg合金的物相主要为α-Al基体和共晶Si.共晶体组织[α-Al+单质Si]在α-Al基体上呈连续网络状分布.XOY和XOZ截面的组织均有粗晶区、细晶区和热影响区.经退火处理后,连续网络状分布的共晶Si发生部分溶解和断裂,合金的强度降低,但硬度略微升高.经T6处理后,共晶体呈规则几何形状零散地镶嵌在α-Al基体上,合金的抗拉强度下降,但屈服强度略有提升,塑性明显增强.综合比较,T6处理更适合作为选区激光熔化成形AlSi10Mg合金的后续热处理.