热处理对激光选区熔化MS1模具钢组织及力学性能的影响

Effect of Heat Treatment on Microstructure and Mechanical Properties of MS1 Alloy Formed by SLM

利用激光选区熔化(selective laser melting,SLM)成形技术对MS1模具钢的成形工艺进行研究,获得了均匀致密的打印态试样。对打印态试样进行850℃×1 h固溶+550℃×4 h时效热处理,并分别对打印态和热处理态试样进行显微组织和力学性能分析。结果表明:MS1模具钢的SLM打印态的合金组织主要由板条状马氏体和奥氏体组成,组织均匀细小,但存在微小缩孔;热处理改善了MS1模具钢的打印态组织,消除了缩孔缺陷。热处理后,MS1模具钢内部析出了强化相,使其强度增大,塑性降低。其中,屈服强度提升超过1倍,抗拉强度提升70%以上,硬度提升82%以上,延伸率由10.7%降至5.6%。

In this study,we investigated the influence of process parameters on the relative density of MS1 alloy manufactured by selective laser melting(SLM).The effect of post-heat treatments with 850℃×1 h solid solution +550℃×4 h aging process on the microstructure and mechanical properties was elucidated.The SLMed MS1 alloy with high density and high performance was achieved.The results show that the structure of the SLM as-built alloy is mainly composed of lath marensite and austenite,with small size and uniform distribution,but there are tiny shrinkage holes in the as-bulit alloy.The post-heat treatments improve the as-built structure of MS1 alloy and eliminate pore defects.After heat treatment,much strengthening phases are precipitated in MS1 alloy,which increases its strength and reduces the ductility.The yield strength is increased by more than 1 time,the tensile strength is increased by more than 70%,the hardness is increased by more than 82%,and the elongation rate is reduced from 10.7% to 5.6%.