热等静压/热处理工艺对激光选区熔化成形GH4169合金微观组织与拉伸性能的影响

采用激光选区熔化(SLM)成形技术制备GH4169合金,利用金相显微镜(OM)、扫描电子显微镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)等分析热等静压/热处理工艺对SLM成形GH4169合金微观组织及拉伸性能的影响规律.结果表明:沉积态合金组织中,沿沉积方向的晶粒为柱状晶,晶粒内枝晶组织细小,枝晶间分布大量Laves相;经热等静压后,合金中的气孔及Laves相可被有效消除,沿沉积方向的晶粒转变为等轴晶;经980℃/1 h固溶处理后,合金中的晶界处析出大量短棒状δ相.热等静压/热处理后G H4169合金试样的室温及650℃拉伸性能均高于锻件标准要求的力学性能指标,且温度对断裂方式影响不大.

Effects of hot isostatic pressing and heat treatment process on microstructure and tensile properties of selective laser melting manufactured GH4169 alloy

GH4169 alloys were manufactured by selective laser melting(SLM).The microstructure evolution and tensile properties of GH4169 alloys during hot isostatic pressing(HIP)and heat treatment(HT)process were analyzed by OM,SEM,EBSD and TEM.The results show that the grains of the as-deposited samples in the building direction are columnar,exhibit very fine cellular-dendritic structure with fine Laves phases precipitating in the interdendritic region.Most of porosities and Laves phases disappear after HIP,and the microstructure parallel to the building direction is transformed into equiaxed grains.Short rod-like δ phases are precipitated along grain boundaries after annealing at 980℃ for 1 h.The tensile properties at room temperature and 650℃of specimens after HIP and HT are higher than those of the standard requirements for the forgings,and the temperature has a little influence on the fracture mode.