激光熔覆Al0.1CoCrFeNi高熵合金涂层的组织和性能

Microstructure and properties of Al0.1CoCrFeNi high entropy alloy coating fabricated by laser cladding

采用激光熔覆技术在H13钢表面制备了Al0.1CoCrFeNi高熵合金涂层。结果表明,涂层具有单相FCC结构,涂层与基材结合处组织为柱状晶,其他区域为等轴晶;涂层截面显微硬度最高可达560.2 HV0.5,约为基体硬度的2.5倍。涂层表现出明显优于基材的抗热冲击性能。在600℃和800℃下分别循环50次后涂层均未产生裂纹,但是在1000℃高温下循环7次后,基体断裂,而涂层及涂层与基体结合处并没有明显的裂纹。涂层的摩擦因数和磨损率均低于基材,分析表明涂层以氧化磨损为主,而基材的磨损机理为氧化磨损伴随疲劳磨损的混合机制。

Al0.1Co Cr Fe Ni high-entropy alloy coating on the surface of H13 steel was prepared by using laser cladding technology.The results show that the structure of Al0.1Co Cr Fe Ni high-entropy alloy coating is single phase FCC type,showing as columnar grains at the junction of coating and substrate steel,while as equiaxed grains in other regions;and the maximum microhardness on the coating section is up to 560.2 HV0.5,which is about 2.5 times of that of the substrate.The coating exhibits better thermal shock resistance than that of the substrate.No cracks are found in the coating after thermal shocking at 600℃and 800℃for 50 cycles,but when undergone 7 cycles at a high temperature of 1000℃,the steel substrate is broken while there is no obvious cracks in the coating and the junction zone of coating and substrate.Both the friction coefficient and wear rate of the coating are lower than that of the substrate,which indicates oxidation wear is the main wear mechanism for the coating,while the substrate steel shows mixed mechanisms of oxidation wear and fatigue wear.