均匀化热处理对选区激光熔化GH4169合金不同成形方向组织和力学性能的影响

Effects of Homogenization Heat Treatment on Microstructure and Mechanical Properties of GH4169 Alloy in Different Forming Directions Fabricated by Selective Laser Melting

采用激光选区熔化技术成形GH4169试样。研究了与基板平行的x-y成形方向、与基板垂直的z成形方向以及与基板成45°成形方向的试样,且采用了3种热处理制度:标准固溶+时效,及真空状态下分别在1040、1100℃下保温1.5 h均匀化处理后再进行标准的固溶+时效处理。研究了不同成形方向及不同热处理状态对试样微观组织及拉伸性能的影响。结果表明:与基板平行的x-y成形方向的增材试样为细小的“胞状”晶粒结构,与基板垂直的z方向成形试样的微观组织为柱状枝晶结构,与基板成45°方向的成形试样微观组织中有胞状晶和柱状晶。经过均匀化处理的GH4169合金,组织缺陷可在一定程度上得以消除,有利于提高激光选区熔化增材GH4169合金试样的综合力学性能。

GH4169 samples were formed by laser selective melting technology,and the x-y forming direction parallel to the substrate,the z forming direction perpendicular to the substrate,and the 45°forming direction to the substrate were prepared.Three heat treatment systems were adopted:standard solid solution+aging,the standard solution+aging treatment was carried out after the homogenization treatment at 1040℃for 1.5h in the vacuum state,and the standard solution+aging treatment was carried out after the homogenization treatment at 1100℃ for 1.5 h in the vacuum state.The effects of different forming directions and different heat treatment states on the microstructure and tensile properties of the specimens were studied.The results show that the additive specimens in the x-y forming directions parallel to the substrate have a fine“cellular”grain structure,perpendicular to the substrate.The microstructure of the z-direction formed sample is a columnar dendritic structure,and the microstructure of the formed sample at a direction of 45°from the substrate has cellular crystals and columnar crystals.The homogenized GH4169 alloy eliminates the micro-segregation of elements in the GH4169 alloy,can eliminate the structural defects and residual stress to a certain extent,which is beneficial to improve the comprehensive mechanical properties of the laser selective melting additive GH4169 alloy sample.