激光增材制造钢的后热处理研究现状

激光增材制造为非平衡凝固过程,容易产生组织应力及热应力,出现变形和开裂等现象。通过后热处理,能够达到改善激光增材制造金属构件组织、消除缺陷、优化性能的目的,因此,后热处理制度的优化成为合金钢件增材制造亟待解决的关键技术。针对合金钢的激光增材制造,综述了近年来激光增材制造钢的后热处理工艺的研究现状。选择典型的17-4PH不锈钢及316L不锈钢等增材制造钢,研究不同后热处理规范对组织形态、第二相质点分布的影响;及其相应的热处理前后的拉伸强度及伸长率等力学性能的变化情况。通过热处理规范的合理选择,能够显著改善增材制造钢的组织及机械性能。

Research Status of Post-heat Treatment of Steel Fabricated by Laser Additive Manufacturing

Nonequilibrium solidification during AM of laser was likey to lead to thermal stress and structral stess, which was the source of distortion, cracking, etc. Through post-heat treatment, the aim of microstructral improvement, defect inhibitation and property optimization can be achieved. Estabishing the rules of post-heat treatment was the key issue for alloy steel fabricated by AM. In this paper, the recent research status of the post-heat treatment process of steel fabricated by AM was summerized. 17-4PH stainless steel, 316L stainless steel and other typical alloy steel were selected to investigate influences of different post-heat treatment process on the evolution of micrstructure and the distribution of second phase paricles. At the same time, the variation of tensile strength and elongation before and after post-heat treatment was investigated comparatively. It can be found, through post-heat treatment optimized, microstructure and mechanical property can be improved distinctively.