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针对钢质热负荷部件易产生热疲劳损伤的问题,采用同步送粉激光熔覆工艺,在活塞用中碳钢38Mn VS6表面制备了Co-Cr-W抗热疲劳合金涂层。利用光学显微镜、SEM、EDS及XRD对熔覆层显微组织和成分分布进行了分析,利用显微硬度计和实验室开发的激光热疲劳实验平台对熔覆层的显微硬度和热疲劳性能进行了测试。结果表明,熔覆层与基体冶金结合,无气孔、裂纹等缺陷。由于固溶强化、弥散强化效应,熔覆层具有较高的强度。送粉率为5.9 g/min时,涂层显微硬度在530~590 HV0.1之间,是基体硬度的2倍左右;熔覆层试样抗热疲劳性能相较于基体材料试样得到了显著的提高。
Aimed at the problem of thermal fatigue damage to the steel thermal load parts, Co-Cr-W thermal fatigue resistant alloy coating was prepared on the surface of medium carbon steel 38Mn VS6. The microstructure and composition distribution of the cladding layer were analyzed by optical microscope, SEM, EDS and XRD. The microhardness and thermal fatigue properties of the cladding layer were analyzed by microhardness tester and laser thermal fatigue test platform developed in the laboratory taking the test. The results show that the cladding layer is metallurgically bonded with the substrate without defects such as pores and cracks. Due to solid solution strengthening, dispersion strengthening effect, cladding layer has high strength. When the feeding rate is 5.9 g / min, the microhardness of the coating is between 530 and 590 HV0.1, which is about 2 times of the hardness of the substrate. The thermal fatigue resistance of the coating is better than that of the base material Significantly improved.