激光熔覆制备高熵合金涂层耐磨性研究进展

Research progress in wear resistance of high entropy alloy coatings prepared by laser cladding

机械零部件的摩擦磨损主要发生在材料表面,约有80%的零件工作失效是由表面磨损造成的。摩擦磨损增加了材料和能量的损耗,降低了可靠性和安全性。使用激光熔覆技术在基体表面制备高熵合金涂层的方法,能够使涂层与基体实现良好的冶金结合,以达到提升表面耐磨性能的目的。影响高熵合金涂层耐磨性的因素主要有涂层材料的力学性能,如硬度、塑性和韧性;熔覆过程中产生的缺陷,如表面粗糙不平、气孔和裂纹;摩擦工况,如高温环境和腐蚀环境。本文分析总结了激光熔覆高熵合金涂层的耐磨性影响因素及强化机制。首先,阐明了激光工艺参数(激光功率、激光扫描速度、光斑直径)和后处理工艺(热处理和轧制)对涂层质量及性能的影响;其次,概述了组元元素选择、高温环境和腐蚀环境对涂层耐磨性的影响;最后,对激光熔覆技术制备高熵合金涂层存在的问题进行归纳分析,并对未来的发展趋势进行了展望,如基于远平衡态的材料设计理论研发新材料、利用电场-磁场协同或激光-超声振动复合等新工艺提升涂层耐磨性等。

The friction and wear of mechanical parts mainly occurs on the surface of the material,and about 80%of the failures of parts are caused by surface wear.Friction and wear increase the loss of material and energy,and reduce the reliability and safety.Using laser cladding technology to prepare a high entropy alloy coating on the surface of the substrate can achieve a good metallurgical combination between the coating and the substrate,so as to achieve the purpose of improving surface wear resistance.The main factors affecting the wear resistance of the high entropy alloy coating are the mechanical and physical properties of the coating material(such as hardness,plasticity and toughness),defects generated during the cladding process(such as surface roughness,pores and cracks),friction conditions(such as high temperature environment and corrosive environment).In this paper,the influencing factors and strengthening mechanism of laser cladding high entropy alloy coatings were reviewed and summarized.First of all,the influence of laser process parameters(such as laser power,laser scanning speed,spot diameter)and post-treatment processes(such as heat treatment and rolling)on the quality and performance of the coating were explained.Secondly,the influence of component element selection,high temperature environment and corrosive environment on the wear resistance of the coating was described.Finally,the problems existing in the preparation of high entropy alloy coatings by laser cladding technology were analyzed,and the future development trends were forecasted,such as developing new materials based on far-equilibrium material design theory,using electric field-magnetic field synergy or laser-ultrasonic vibration composite technology to improve the wear resistance of coatings,etc.