H11钢表面激光熔覆Al2CoCrCuFeNi高熵合金涂层组织性能

Microstructure and Properties of Al2CoCrCuFeNi High-entropy Alloy Coating by Laser Surface Cladding on H11 steel

采用激光熔覆技术在H11钢表面制备厚度为150μm的Al2CoCrCuFeNi高熵合金涂层,研究了涂层的组织结构、显微硬度和耐磨性能。实验得到优化的多道搭接工艺参数为电流270 A、扫描速度3 mm/s、离焦量-14 mm、搭接率40%。在涂层中形成以微观组织为枝晶和枝晶间组织的简单固溶体。熔覆层上部组织由等轴晶粒组成,而下部组织由柱状晶粒组成,并且基体/涂层之间形成冶金结合。涂层的平均显微硬度比基体250 HV的硬度增加了70%;涂层试样的磨损率只有基体的30%,相比H11钢基体,高熵合金熔覆层显微硬度和耐磨性都大大提高。

Preparation of Al2CoCrCuFeNi high-entropy alloy coating with thickness of 150μm on the surface of H11 steel by laser cladding technology was studied.The optimized multi-pass lap process parameters were obtained:the current was 270 A;the scanning speed was 3 mm·s-1;the defocus was fixed at-14 mm;40%track overlapping condition was used.The microstructure,microhardness and wear resistance of the coating were investigated.The results show that Simple solid solution phases were formed in the coating layer with a typical microstructure at the top of the cladding zone consists of equiaxed grains while that at the bottom consists of columnar grains,And metallurgical bonding is formed between the substrate/coating.The average microhardness of the coating layer shows 70%enhancement compared with that(HV 250)of the H11 substrate;The wear rate of the coated sample is 30%that of the H11 substrate.The coating layer exhibits great enhancement in microhardness and wear resistance compared with the H11 substrate.