文章摘要
Ni基合金激光熔覆裂纹机理研究
Study on Mechanism of Cracking in Cladding Layer byNi-Based Alloy Laser Cladding
投稿时间:2019-03-26  修订日期:2019-05-02
DOI:
中文关键词: 激光熔覆  镍基合金  裂纹机理  微观组织  热应力
英文关键词: laser cladding  nickel-based alloy,  crack mechanism,  microstructure  stress.
基金项目:中央高校基本科研业务费资助(项目批准号:DUT18JC13).
作者单位E-mail
李琦 大连理工大学机械工程学院 liqi_2016@163.com 
李涛 大连理工大学机械工程学院 litao@dlut.edu.cn 
石博文 大连理工大学机械工程学院  
吴祖鹏 大连理工大学机械工程学院  
张洪潮 大连理工大学机械工程学院  
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中文摘要:
      激光熔覆得到的Ni基合金熔覆层容易出现裂纹,这是导致Ni基合金熔覆层失败的主要因素。本文基于实验及微观检测分析,以Ni60熔覆层为研究对象,从组织和应力方面对激光熔覆过程中熔覆层裂纹的开裂及扩展机理进行了研究。综合熔覆层微观组织、物相以及断口形貌分析发现,熔覆层不同位置晶体组织差异显著,材料硬度与裂纹敏感性随硬质相分布的增加而升高,Ni60熔覆层的裂纹属于准解离的脆性断裂,裂纹萌生于熔覆层顶部,并沿硬质相向内部规律性扩展。本文根据热残余应力模型与Griffith脆性断裂强度模型建立了涂层开裂判据,为裂纹的产生提供理论基础,并在此基础上提出相应的裂纹消除方法。
英文摘要:
      The Ni-based alloy coating obtained by laser cladding is prone to cracking, which is the main factor leading to the failure of the Ni-based alloy coating. Based on the experimental and microscopic analysis and analysis, Ni60 coating was used as the research object. The mechanism of cracking and propagation of cracks in laser cladding coatings was studied from the aspects of microstructure and stress. The microstructure, phase and fracture morphology of the composite coating showed that the crystal structure of the coating was significantly different at different locations. The hardness and crack sensitivity of the coating increased with the increase of the hard phase distribution. The crack of Ni60 coating was quasi-dissociation. The brittle fracture, which occurs at the top of the cladding layer and extends regularly along the interior of the hard phase coating. Based on the thermal residual stress model and the Griffith brittle fracture strength model, the cracking criterion of the coating is established to provide a theoretical basis for the crack generation. Based on this, the corresponding crack elimination method is proposed.
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