激光熔覆高熵合金气门的组织和性能研究

The study on microstructure and properties of laser cladding high entropy alloy valve

采用激光熔覆技术在发动机气门工作锥面熔覆了AlCoCrFeNiTi高熵合金涂层,采用光学显微镜和扫描电镜观察了熔覆层的组织形貌,采用能谱仪观察了枝晶和枝晶间区域各元素的分布情况,采用X射线衍射仪器对熔覆层结构相组成进行了分析,采用显微维氏硬度计对熔覆层的机械性能进行了测试。结果表明:熔覆层区域呈典型的树枝晶形貌,熔覆层与基体结合处区域呈胞状晶形貌,基体与熔覆层结合良好无明显缺陷。在硬度方面,熔覆层的平均硬度为620 HV,是基体平均硬度的2.4倍。在高温环境下,熔覆层区域的平均硬度下降至520 HV。

In this study,AlCoCrFeNiTi high entropy alloy coating was coated on the working cone of engine valves by laser cladding technology.The morphology of cladding layer was observed by optical microscope and scanning electron microscope.The distribution of elements between dendrites and dendrites was observed by energy spectrum.The structure and phase composition of the coating were analyzed by X-ray diffraction.The mechanical properties of the clad layer were tested by micro-Vickers hardness tester.The results show that the cladding layer has a typical dendrite shape in the cladding layer area,and the cladding layer has a cytotoxic shape in the bonding area with the matrix,and there is no obvious defects in the bonding between the matrix and the cladding layer.In terms of hardness,the average hardness of the cladding layer is 620 HV,which is 2.4 times higher than that of the substrate.Under high temperature,the average hardness of cladding layer decreases to 520 HV.