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采用高功率半导体激光器在45#钢圆棒表面制备了Ni25、Co2和316L多层熔覆层,用扫描电镜(SEM)、X射线衍射仪(XRD)对熔覆层的微观组织及物相进行表征,并测试涂层试样的硬度与耐磨性能。结果表明,熔覆层组织均匀、致密,晶粒细小,与基体成冶金结合;激光多层熔覆时,熔覆层经多层重叠扫描,重复融化凝固造成层与层结合区存在一明显白亮带,层内组织在该处存在明显分层现象;Ni25合金熔覆层主要物相有γ-Ni固溶体、BNi3、B2Fe3Ni3、C-Fe-Si等;Co2熔覆层主要由γ-Co、γ-Ni固溶体等组成;多层熔覆层硬度和耐磨性相较于基体,有较大提高,Co2合金熔覆层平均硬度值最高,达到了584.7HV0.3,多层熔覆层经过多次重叠扫描,重复融化凝固熔覆层硬度更加均匀。
Ni25, Co2 and 316L multilayers were prepared on the surface of 45 # steel rod by using high power semiconductor laser. The microstructure and phase of the cladding were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) Characterize and test the hardness and wear resistance of the coated samples. The results show that the microstructure of the cladding layer is uniform and compact with fine grains and metallurgical bond with the substrate. When the cladding layer is overlapped by laser scanning, the cladding layer is repeatedly melted and solidified, In the Ni25 alloy cladding layer, the main phases are γ-Ni solid solution, BNi3, B2Fe3Ni3, C-Fe-Si and so on. The Co2 coating mainly consists of γ-Co, γ -Ni solid solution, etc. The hardness and wear resistance of the multi-layer coating are greatly increased compared with the matrix, the average hardness of the Co2 alloy cladding layer is the highest, reaching 584.7HV0.3, Sub-overlap scanning, repeated melting and solidification coating hardness more uniform.