选区激光熔化FGH4096高温合金的组织与性能  

Microstructure and Mechanical Properties of Powder Metallurgy Superalloy FGH4096 Fabricated by Selective Laser Melting

作　　者：郝志博 田甜 黎兴刚 燕青芝[1] 葛昌纯[1] 颜永年 Hao Zhibo;Tian Tian;Li Xinggang;Yan Qingzhi;Ge Changchun;Yan Yongnian(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;SUSTech Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen 518055 China;Shenzhen Key Laboratory for Additive Manufacturing of High-Performance Materials,Shenzhen 518055 China;Jiangsu Yongnian Laser Forming Technology Company,Kunshan 215300,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]南方科技大学前沿与交叉科学研究院,广东深圳518055 [3]深圳市高机能材料增材制造重点实验室,广东深圳518055 [4]江苏永年激光成形技术有限公司,江苏昆山215300

出　　处：《稀有金属》2020年第5期476-484,共9页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51171016);北京市科技新星计划项目(xx2018036);深圳市高机能材料增材制造重点实验室项目(ZDSYS201703031748354)资助。

摘　　要：以等离子旋转电极法制备的FGH4096粉末为原材料,利用选区激光熔化(selective laser melting,SLM)技术制备了FGH4096合金,合金致密度达99.3%。研究了SLM沉积态、直接时效态、固溶+时效态的组织和拉伸性能。SLM沉积态FGH4096合金由柱状晶构成,垂直熔池边界生长,柱状晶内排列着精细的树枝结构或等轴结构,以奥氏体γ相为主,少量的γ′相和碳化物沿树枝结构和等轴结构边界析出;直接时效处理后,大量三次γ′相析出,树枝结构或等轴结构边界粗化;固溶+时效后,回复和再结晶的发生,合金晶粒呈不规则形状,树枝结构和等轴结构消失,少量一次γ′相和碳化物在晶界析出,晶内分布少量二次γ′和大量均匀的三次γ′相。SLM沉积态FGH4096室温拉伸塑性好,热处理后强度明显提高,塑性下降,直接时效态屈服强度和拉伸强度最高,接近锻造状态。3种状态拉伸断口呈穿晶断裂,随着强度的提高,直接时效态拉伸断口出现数量较多的沿晶断裂区域。FGH4096 alloy was prepared by selective laser melting(SLM)of metal powders produced by plasma rotating electrode process.The alloy density could reach 99.3%.The microstructure and tensile properties of the SLM as-deposited,directly aged,and solid solution+aged alloys were studied,respectively.The as-deposited FGH4096 alloy was composed of columnar crystals which grew perpendicularly at the melt pool boundary and consisted of fine dendritic or equiaxed substructure.A small number ofγ′phase particles and carbides precipitated along the boundary of dendritic and equiaxed structure in the as-deposited FGH4096 alloy with austeniteγphase as main phase.The microstructure of the directly aged alloy indicated a large number of tertiaryγ′phase precipitates and coarsened grain boundaries of dendritic and equiaxed substructures.After solution+ageing treatment,the grains were irregularly shaped,and the dendritic and equiaxed substructures disappeared because of recovery and recrystallization.A small number of primaryγ′phase particles and carbides precipitated at grain boundaries,while a small number of secondaryγ′particles and a large number of uniform cubic tertiaryγ′phase particles precipitated within the grain.The as-deposited FGH4096 had better ductility at room temperature.Although the strength increased significantly after heat treatment,the plasticity decreased.The yield strength and tensile strength of the directly aged alloy were the highest and close to the forging state.Tensile fractures of all three kinds of SLM alloys showed transgranular fractures.With the increase of the strength,the fracture appearance at the directly aged state exhibited a higher fraction of the transgranular fracture than that at the as-deposited state.

关 键 词：FGH4096高温合金 选区激光熔化 显微组织 拉伸性能 

分 类 号：TG665[金属学及工艺—金属切削加工及机床] V252[一般工业技术—材料科学与工程]