激光熔覆镍基合金涂层裂纹形成机理及匹配方法的研究  

Study on Crack Formation Mechanism and Matching Method of Laser Cladding Nickel-based Alloy Coating

作　　者：王伟[1] 孙文磊[1] 周浩南 邢学峰 杨凯欣 于江通 WANG Wei;SUN Wenlei;ZHOU Haonan;XING Xuefeng;YANG Kaixin;YU Jiangtong(School of Mechanical Engineering,Xinjiang University,Xinjiang 830047,China)

机构地区：[1]新疆大学机械工程学院,新疆乌鲁木齐830047

出　　处：《热加工工艺》2022年第14期83-88,共6页Hot Working Technology

基　　金：自治区重点实验室开放基金项目(2020520002);新疆克拉玛依重大专项项目(2018ZD002B)。

摘　　要：分别在45钢和316L不锈钢表面熔覆Ni35、Ni45、Ni60、Ni62镍基合金粉末,采用EDS对镍基合金涂层裂纹区域的元素进行检测,探究了镍基合金涂层裂纹的形成机理,并结合熔覆层裂纹渗透探伤结果,从材料组分和热物性两方面综合考虑,研究了镍基合金材料与基体材料的匹配对涂层裂纹的影响。采用M-2000型磨损试验机和HXD-1000型显微硬度计分别对熔覆层及基体的耐磨性能和硬度进行了测试。结果表明:B、C、Si等元素在镍基合金涂层裂纹区域发生了严重偏析,熔覆层裂纹形成的主要原因是在涂层最后凝固阶段内应力和硬脆相及夹杂物大量偏聚共同作用所致。镍基合金涂层组分及与基材热物性的差异对涂层开裂敏感性的影响重大,且涂层中硬质相元素含量的提高及与基材热物性差异的加大均会提高涂层开裂倾向。故而在满足基体材料表面改性需求的前提下,通过选择硬脆相元素含量相对较少且与基材热物理性相近的熔覆材料可以有效降低涂层开裂敏感性。此外,本文采用的4种镍基合金涂层在耐磨性和硬度方面均优于基材(45钢和316L不锈钢),其对基材表面耐磨性的增强及硬度的提高具有较为出色的作用。Ni35, Ni45, Ni60 and Ni62 nickel-based alloy powders were coated on 45 steel and 316L stainless steel,respectively. The elements in the crack area of nickel-based alloy coating were detected by EDS, and the formation mechanism of the nickel-based alloy coating cracks was explored. In combination with the penetration flaw detection results of the cladding layer, the influence of the matching of nickel-based alloy material and the base material on the coating cracks was studied from the material composition and thermal physical properties. In addition, the wear resistance and hardness of the cladding layer and the substrate were tested using M-2000 type abrasion tester and HXD-1000 type microhardness tester. The results show that B, C, Si and other elements have segregated seriously in the crack area of the nickel-based alloy coating.The main reason for the crack formation of cladding layer is the joint action of internal stress, hard brittle phase and a large amount of segregation of inclusions in the final solidification stage of the coating. The composition of the nickel-based alloy coating and the difference of thermophysical properties between the coating and the substrate have great influence on the cracking sensitivity of the coating.The increase of the content of hard phase elements and the increase of the difference between the coating and the substrate improve the cracking tendency of the coating. Therefore, on the premise of meeting the surface modification requirements of the substrate, the coating cracking sensitivity can be effectively reduced by selecting the cladding materials with relatively small content of hard brittle phase and similar to the substrate thermal physical reason. In addition, the four kinds of nickel-based alloy coatings are superior to the substrate(45 steel and 316 L stainless steel) in terms of wear resistance and hardness, and have excellent help in enhancing the surface wear resistance and hardness of the substrate.

关 键 词：激光熔覆 镍基合金 裂纹 材料匹配 硬质相 

分 类 号：TG174.4[金属学及工艺—金属表面处理]