纳米氧化铈增强TC11合金表面MCrAlY熔覆涂层的热震行为  

Thermal Shock Behaviors of Nano-cerium Oxide Reinforced MCr Al Y Cladded Coatings on TC11 Alloy

作　　者：沈清[1] 王宏宇[1] 吴志奎[1] 金镜[1] 程满[1] 

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《稀土》2015年第3期126-130,共5页Chinese Rare Earths

基　　金：中国博士后科学基金项目(2011M501172);江苏省自然科学基金项目(BK2011479);江苏省博士后科学基金项目(1102114C);江苏省精密与微细制造重点实验室开放基金项目(KFA11250-04);江苏省光子制造科学与技术重点实验室开放基金(GZ201203)

摘　　要：考察了不同含量的纳米氧化铈增强TC11合金表面MCrAlY熔覆涂层的热震行为,并在分析涂层热震裂纹形成过程的基础上探讨了纳米氧化铈对涂层热震行为的作用机理。结果表明,未加纳米氧化铈的涂层,经30次热震后其横切面上分布有源自表面的两条贯穿性裂纹,此时涂层已趋于失效。添加纳米氧化铈后,涂层热震裂纹的形成发生了变化,由从表面萌生向内扩展逐渐转变为从界面萌生向外及横向扩展;当纳米氧化铈的添加量为4%时,涂层本身强度与界面处结合强度匹配适当,裂纹的萌生取向消失即裂纹既不会优先从表面开始也不会优先从界面开始,此时涂层的整体热震性能得到显著改善。Thermal shock behaviors of laser cladding MCrAlY coatings strengthened by different contents of nano-cerium oxides on TC11 alloy were investigated.Based on the forming process analysis of coating thermal shock cracks,the function mechanism of nano-cerium oxides on coating thermal shock behaviors was discussed.Results indicate that there are two perfoliate cracks initiated from the top surface at cross section after 30 thermal shock cycles without adding nano-cerium oxides.It means the coating has tended to failure.The formation of thermal shock cracks has changed after adding nano-cerium oxides,cracks initiated from the surface expand to inside turn into cracks initiated from bonding zone expand to outside and transverse.The strength of the coating matches with the one of the bonding zone appropriately when the addition of nano-cerium oxides reaches 4%(mass fraction),which makes the orientation of crack initiation to disappear,namely,the crack initiation will start from neither top surface nor bonding zone.The thermal shock resistance of the coating in the stage is improved significantly.

关 键 词：钛合金 高温防护涂层 热震性能 纳米氧化铈 激光熔覆 

分 类 号：TG174.4[金属学及工艺—金属表面处理]