热处理对FGH95合金激光成形定向凝固显微组织的影响  

Effect of Heat Treatment on the Laser Metal Forming Directional Solidification Microstructure

作　　者：冯莉萍[1] 黄卫东[1] 林鑫[1] 杨海欧[1] 杨健 

机构地区：[1]西北工业大学凝固技术国家重点实验室,710072

出　　处：《应用激光》2002年第2期150-154,共5页Applied Laser

基　　金：973国家重点基础研究发展规划专题(No.G2000067205-3);863国家高技术研究发展计划(No.2001AA337020)资助

摘　　要：本文利用高温合金FGH95在定向凝固单晶合金DD3基材上进行激光多层涂覆实验,得到了具有细小定向凝固柱状枝晶组织的试样。对激光金属成形定向凝固试样进行了标准热处理,深入研究了热处理前后凝固显微组织的变化规律。研究发现,处理前涂层中的组织为白色的枝晶干和黑色的枝晶间交替排列,枝晶一次间距约为10μm,处理后看不出明显的枝晶间与枝晶干分界,只是基体上弥散沉积了白色的富Nb块状碳化物,枝晶间和枝晶干区域在处理前所存在的尺度大小和形态迎然不同的γ′相在处理后尺度分布变得均匀。各合金元素经热处理后,偏析现象均有不同程度的减轻。Laser multi-layer cladding experiments were performed by using the substrate of DD3 single crystal as substrate and powder FGH95 as cladding material, and sample with superfine directional solidification microstructure have been obtained. The effect of standard heat treatment on the solidification microstructure in the cladding sample was investigated. It was found that the solidification microstructure was greatly influenced by heat treatment. In the original cladding sample, the white dendrites trunk and black interdendrites zone were arrayed along the heat flow alternatively with the primary spacing of the sample of about 10μm. After heat treatment, there are no apparently interface of dendrites trunk and interdendrites in the sample. Only the white block phases that rich in element Nb were deposited on the matrix. The γ' phase deposits with different size and morphology in different area (dendritic trunk and in the interden-drites) becomes uniformed through heat treatment. In addition, the certain element segregation formed during the laser cladding experiment in the cladding layers have been alleviated to some extent after heat treatment.

关 键 词：激光金属成形 定向凝固 显微组织 热处理 FGH95合金 定向凝固方法 

分 类 号：TG665[金属学及工艺—金属切削加工及机床] TG111.4