镍基合金激光熔覆MCrAlY涂层基体裂纹的成因与控制  

Originate Mechanism and Prevent Process of Substrate Cracks in Laser Cladding MCrAlY Coatings on Nickel-Based Superalloy

作　　者：王宏宇[1,2] 左敦稳[1] 陆英艳[1] 许鸿昊[1] 

机构地区：[1]南京航空航天大学江苏省精密与微细制造技术重点试验室,南京210016 [2]江苏大学机械工程学院,江苏镇江212013

出　　处：《航空材料学报》2008年第6期57-60,共4页Journal of Aeronautical Materials

基　　金：高等学校博士学科点专项科研基金(20060287019);江苏省摩擦学重点试验室开放基金(kjsmcx07001);江苏省研究生科研创新计划资助项目(CX08B-039Z)

摘　　要：在分析激光熔覆涂层基体裂纹形成机理的基础上,针对采用激光熔覆技术在镍基合金基体上制备MCrA lY涂层存在基体裂纹的问题,提出了缓冷处理的止裂措施,研究了将熔覆后的涂层置于300℃下保温30m in随炉缓冷和置于已预热至300℃的保温箱中随箱缓冷两种缓冷工艺对基体裂纹的控制行为。结果表明:镍基合金激光熔覆MCrA lY涂层基体裂纹主要是由于熔覆过程中的快速冷却所致;两种缓冷工艺均能有效地避免基体裂纹的产生,但保温随炉缓冷处理会引起熔覆层组织粗大、枝晶特征明显等不良影响,而随箱缓冷处理涂层对熔覆层组织并未产生不良影响。Aiming at substrate cracks in the laser cladding MCrAlY coatings on nickel-based superalloy, technological measures for preventing cracks by slow cooling rate treatment were presented based on the originate mechanism of substrate cracks in the paper. Two slow cooling rate treatments were respectively furnace cooling after heat preservation for 30 min under 300 ℃ and cooling in insulated cabinet which was heated to 300℃ , and their prevent behaviors to substrate cracks were discussed. The results show that the reason which originates substrate cracks of the laser cladding MCrAlY coatings on nickel-based superalloy is the rapid-cooling of substrate in the course of laser cladding, and two slow cooling rate treatments can both effectively prevent the originate of substrate cracks. Moreover, the furnace cooling treatment causes coarse microstructure and obvious dendrite characteristic, but the cooling in insulated cabinet doesn＇t produce any negative effect.

关 键 词：激光熔覆 基体裂纹 镍基合金 缓冷处理 

分 类 号：TG156.99[金属学及工艺—热处理]