激光金属成形定向凝固显微组织及成分偏析研究  

INVESTIGATION ON THE MICROSTRUCTURE ANDCOMPOSITION SEGREGATION OF THE LASER METALFORMING DIRECTIONAL SOLIDIFICATION

作　　者：冯莉萍[1] 黄卫东[1] 李延民[1] 杨海欧[1] 林 鑫[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：《金属学报》2002年第5期501-506,共6页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划项目(973)G2000067205-3;航空基金重点项目97z53002资助

摘　　要：利用高温合金Rene95粉末在镍基高温合金基材上进行激光多层涂覆,研究熔覆层中凝固显微组织的生长特性,基于对柱状晶向等轴晶转化理论的分析,证实通过控制工艺参数组合,可获得具有良好取向的单道多层、多道搭接多层定向凝固涂层和圆环的定向凝固试样,涂层内部的定向凝固柱状枝晶组织细密,枝晶一次间距为5-30μm,二次臂很小或者完全退化,涂层内无明显的成分偏析现象。Laser metal forming directional solidification experiments were performed by using nickel-base superalloy as substrate and powder Rene95 as cladding material. The solidification microstructure of the cladding layer was investigated. According to the theory of columnar/equiaxed transition (CET) in front of the solid/liquid interface, it was found that, in the single path multi-layer cladding layers and multi-path multi-layer cladding layers, the microstructure with the same crystallographic orientation as the substrate was obtained by reasonably selecting the processing parameters. Round directional solidification sample of laser multi-layer cladding was acquired by combining the multi-layer laser cladding and computerized numerical control (CNC) technique. The microstructure of the cladding layers is consisted of regular columnar dendrites. The primary spacing of dendrites is about 5-30 mum and the secondary arm is small or even degenerated. Energy spectrum analysis showed that there was no obvious composition segregation in the cladding layers.

关 键 词：激光金属成形定向凝固 显微组织 成分偏析 

分 类 号：TG244[金属学及工艺—铸造] TG113