Crack Behavior of Ni60A Coating Prepared by Laser Cladding on a Tilted Substrate
Crack Behavior of Ni60A Coating Prepared by Laser Cladding on a Tilted Substrate
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DOI：
10.3390/coatings12070966
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发表时间：
2022-07
期刊：
影响因子：
3.4
通讯作者：
Bowen Shi;Xiaokai Mu;H. Zhan;Linhui Deng;Tao Li;Hong-chao Zhang
中科院分区：
文献类型：
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作者：
Bowen Shi;Xiaokai Mu;H. Zhan;Linhui Deng;Tao Li;Hong-chao Zhang
目前，几乎所有关于激光熔覆裂纹的研究都是基于水平基底的，不能直接应用于在倾斜基底上制备高性能涂层，特别是高硬度涂层。基于倾斜基底上的激光强度分布和能量衰减模型，研究了基底倾斜角度对高硬度Ni60A涂层裂纹行为的影响。结果表明：随着基体倾角的增大，涂层的裂纹率（单元熔覆长度中的裂纹数）增加，但倾角对裂纹机理的影响不显著；不同搭接方向对裂纹有一定影响，向下搭接熔覆制备的涂层由于激光能量损失较大，裂纹率较大。随着基体倾角的增大，塑性流动减少导致残余应力增大，稀释率降低导致断裂强度降低，导致Ni60A涂层开裂率增大。该工作将拓宽激光熔覆技术在齿轮、叶片等复杂零件修复中的应用。
Almost all of the research on cracks in laser cladding is based, at present, on a horizontal substrate, which cannot be directly applied to prepare high performance coatings, especially high hardness coatings, on tilted substrate. In this work, the influence of the substrate’s tilt angle on the crack behavior of high hardness Ni60A coating is studied, based on the laser intensity distribution and energy attenuation models on the tilted substrate. Results show that the cracking rate (the crack number in the unit’s cladding length) of the coating increases with the increasing substrate tilt angle, but the tilt angle has no significant influence on the crack mechanism. The different lap direction has a certain influence on the crack, and the coating prepared by downward lap cladding has a larger cracking rate due to the greater laser energy loss. Furthermore, with the increasing substrate tilt angle, the residual stress increases due to the decreased plastic flow, and the fracture strength decreases due to the decreased dilution rate, which results in the increase in the cracking rate of the Ni60A coating. This work will broaden the application of laser cladding technology on repairing complex parts such as gear and blades.