镍基高温合金表面激光熔覆Incone l738合金层的开裂行为  

Cracking behavior of Inconel 738 alloy on Ni-base superalloy surface by laser cladding

作　　者：时阳[1,2] 陈智君[1,2] 张群莉[1,2] 孔凡志[1,2] 王维夫[1,2] 姚建华[1,2] 

机构地区：[1]特种装备制造与先进加工技术教育部/浙江省重点实验室(浙江工业大学),浙江杭州310014 [2]浙江工业大学激光加工技术工程研究中心,浙江杭州310014

出　　处：《金属热处理》2011年第3期72-76,共5页Heat Treatment of Metals

基　　金：国家自然科学基金项目(50971117);博士科研启动基金(56710203006)

摘　　要：针对镍基高温合金叶片强化与修复的需求,在高温合金K438基体上激光熔覆Inconel 738合金涂层。分析了基体组织及熔覆层中微观缺陷对熔覆层裂纹的影响。结果表明,激光熔覆时大多数裂纹是从基体一侧形成后深入到熔覆层中或产生于层与层之间的搭接区,裂纹沿晶界扩展。沿晶界分布的低熔点共晶物是主要的裂纹源。激光熔覆时,晶界处的γ/γ′低熔点共晶物熔化,形成晶界液膜,冷却时,在残余拉应力的作用下被拉开,形成裂纹,裂纹一旦形成就会沿晶界迅速扩展。In view of the strengthening and repair of Ni-base superalloy blades,laser cladding Inconel 738 powder on the substrate of superalloy K438 was carried out.The effects of the substrate microstructure,microscopic defects of the cladding layer on cracks were investigated.The results show that most of the cracks penetrated into the cladding layer have forming from one side of the substrate or the overlapping zone,and extended along the crystal boundary.The eutectic phase with low melting point is the main sources of the cladding cracks.During the laser cladding,the γ/γ′eutectic phase with low melting point can liquefy,and form grain boundary film.While cooled,the eutectic phase can be pulled apart by the residual tensile stress,leading to the formation of crack,which will rapidly expand along the grain boundary as it forms.

关 键 词：激光熔覆 裂纹 镍基高温合金 

分 类 号：TG156.99[金属学及工艺—热处理]