热处理对激光选区熔化制备Inconel 718合金组织和拉伸性能的影响

采用激光选区熔化工艺(SLM)制备了Inconel 718合金,并对合金分别进行了1050 ℃×1 h固溶和1050 ℃×1 h固溶+720 ℃×8 h+620 ℃×8 h双级时效热处理。结合微观组织、拉伸性能和断裂特征分析,研究了热处理工艺对SLM制备的Inconel 718合金组织和力学性能的影响。结果表明:固溶处理后合金内Laves相溶解,位错密度显著降低,材料的强塑性匹配较打印态得到良好的改善。经过时效热处理后,γ′和γ″强化相析出使合金强度大幅度提高的同时,保留了一定的塑性。

Effect of heat treatment on microstructure and tensile properties of Inconel 718 alloy prepared by selective laser melting

Inconel 718 alloy was prepared by selective laser melting (SLM) process. The solution treatment at 1050 ℃ for 1 h, solution treatment at 1050 ℃ for 1 h and aging treatment at 720 ℃ for 8 h and 620 ℃ for 8 h were respectively applied on the SLM processed alloy. The effect of heat treatment process on the microstructure and mechanical properties of the SLM-Inconel 718 alloy were studied by combining with microstructure analysis, tensile properties analysis and fracture characteristics analysis. The results show that the density of dislocations is significantly reduced associated with Laves phase dissolving after solid solution treatment. Hence the strength-plasticity matching of the alloy is better than that of the as-SLM state. After aging, γ′ and γ″ strengthening phases precipitate out, which greatly increase the strength of the alloy while retaining a certain plasticity.