Y-Hf共掺杂AlCrFeNiCu高熵合金涂层的组织与高温抗氧化性能

Microstructure and High-Temperature Oxidation Resistance of Y-Hf Co-doped AlCrFeNiCu High Entropy Alloy Coating

摘要:

采用高速激光熔覆技术在锆合金棒表面制备了Y-Hf共掺杂的AlCrFeNiCu高熵合金涂层。对涂层的组织结构、显微硬度和耐高温氧化性进行了测试和分析。结果表明：涂层底部与基体之间存在元素的相互扩散，热影响区宽约35 μm，涂层的组织主要由黑色的枝晶区和灰白色的枝晶间区组成。涂层成分均匀，硬度高达830 HV，高熵合金特有的固溶强化、晶格畸变和慢扩散效应是涂层具有高硬度的主要原因。在1200 ℃下氧化90 min后仍能保持涂层的结构完整性，涂层具有较低的氧化速率，氧化过程遵循生长动力学曲线，表面的氧化物主要由Al₂O₃和Cr₂O₃组成，提高了锆合金的高温抗氧化性。

Abstract:

Y-Hf co-doped AlCrFeNiCu high entropy alloy (HEA) coating was prepared on the surface of zirconium alloy rod by high-speed laser cladding (HSLC) technique. The microstructure, microhardness, and high-temperature oxidation resistance of the coating were tested and analyzed. The results show that there is mutual diffusion of elements between the bottom of the coating and the substrate, and the width of the heat affected zone is about 35 μm. The microstructure of the coating is mainly composed of black dendrite zone and gray white interdendrite zone. The composition of the coating is uniform and the hardness is as high as 830 HV. The main reasons for the high hardness of the coating are solution strengthening, lattice distortion and slow diffusion effect. The structural integrity of the coating can be maintained after oxidation at 1200 ℃ for 90 min. The coating has a low oxidation rate, and the oxidation process follows the growth kinetics curve. The oxides on the surface are mainly composed of Al₂O₃ and Cr₂O₃, which improves the high-temperature oxidation resistance of zirconium alloy.