FGH95合金激光成形定向凝固显微组织与性能  

FGH95 superalloy laser metal forming directional solidification

作　　者：冯莉萍[1] 黄卫东[1] 林鑫[1] 杨海欧[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《中国有色金属学报》2003年第1期181-187,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展规划专题基金资助 (G2 0 0 0 0 672 0 5 3 );国家高技术研究发展计划基金资助 (2 0 0 1AA3 3 70 2 0 )

摘　　要：利用FGH95合金粉末在DD3单晶基材和定向凝固镍基高温合金的择优晶面 (与择优晶向垂直的晶面 )上进行激光多层涂覆实验 ,得到了从基材外延生长的单晶涂覆层。涂层由细小柱状枝晶组织组成 ,枝晶一次间距约为 10 μm ,二次臂退化。由于局部凝固条件的不同 ,枝晶干区域的γ′相为球形、枝晶间区的γ′相为立方体形态 ,尺度均小于 0 .1μm。激光涂覆层中的主要元素Cr和Co的偏析比基材铸态组织中的偏析大大减轻。对标准热处理后的试样进行分析表明 :试样中的γ′相主要为方圆形 ,且尺度均匀。涂层中各元素的显微偏析比热处理之前有明显减轻。沿片状力学性能试样柱状晶生长方向进行拉伸 ,强度指标达到同种材料粉末冶金试件的 97.9% ,塑性超过粉末冶金试件。断口分析表明 。Laser multi-layer cladding experiments we re performed on the preferential crystallography surface (plane normal to the pref erential crystallography orientation) of the DD3 single crystal rod and the dire ctional solidification nickel-base superalloy rod by using superalloy FGH95 pow der. Cladding layers growing epitaxially from the substrate can be obtained. The cladding layer consists of thin columnar dendritic, the primary arm spacing of which is about 10 μm, and the secondary arm is degenerated. γ ′ deposits are spherical in the dendritic trunk and cubical in the interdendritic area due to the difference of the local elements aggregation. The sizes of γ ′ phase are less than 0.1 μm. Composition segregation of main elements in the claddin g layer are highly alleviated on comparing with that of the substrate. After hea t treatment, the γ ′ deposits become cubic-spherical in the cladding layer and the size of them is more homogeneous in all of the single crystal cladding layers. Composition segregation is alleviated further after heat treatment. Mech anical measurement shows that yield strength acquires 97.9% of that in powder me tallurgic sample and the plasticity surpasses that in powder metallurgic sample, and the fracture of FGH95 shows plastic fracture.

关 键 词：成分偏析 力学性能 FGH95合金 激光成形 定向凝固 显微组织 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG291[金属学及工艺—金属材料]