激光合成TiC/Ni涂层裂纹控制技术  

Cracking control technology of TiC/Ni coatings prepared by in-situ fabrication through laser cladding

作　　者：赫庆坤[1] 王勇[1] 赵卫民[1] 程义远[1] 

机构地区：[1]中国石油大学机电学院材料系,山东东营257061

出　　处：《焊接学报》2009年第4期21-24,共4页Transactions of The China Welding Institution

基　　金：国家863高技术研究发展计划资助项目(2006AA09A104)

摘　　要：激光熔覆原位合成TiC/Ni涂层开裂严重.从熔覆层金相组织、物相组成、残余应力、宏观形貌和断口观察等角度分析裂纹形成的原因,提出了相应的裂纹控制措施.结果表明,激光合成TiC/Ni涂层裂纹主要是由于硬脆相及残余内应力导致的脆性冷裂纹.通过增大钛粉量,Ti元素与Ni60中的M23C6相发生置换反应:M23C6+Ti→M+TiC.通过加入镍粉或优化工艺参数,可以改善涂层组织,提高塑韧性,降低残余内应力,从而降低裂纹敏感性.There are many cracks in TiC/Ni coatings prepared by in-situ fabrication through laser cladding.The reasons for crack initiation in the coatings were analyzed from the microstructure,the phase composition,the residual stress,the macro morphology and the fracture observation.Corresponding cracking control measures were also proposed.The investigation indicated that the cracks of the TiC/Ni coatings are mainly brittle cold cracks caused by hard brittle phases and internal residual stress.The replacement reaction(M23C6+Ti→M+TiC) occurs by increasing the content of Ti powder.Therefore,cracks of the coatings can be reduced or eliminated.Moreover,intriguing microstructures of the coatings are obtained with enhanced plasticity and toughness and reduced residual stress by nickel powder addtion or by optimizing processing parameters,thus the cracking susceptibility can be decreased.

关 键 词：激光熔覆 原位合成 裂纹控制 置换反应 

分 类 号：TG115.28[金属学及工艺—物理冶金]