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在316不锈钢表面进行激光熔覆Stellite 3、Stellite 21与新型Co基合金(Co-3)试验,分析了熔覆层的显微组织及相成分,研究了硬度分布和耐擦伤机理。试验结果表明,Co-3显微组织均匀、致密,无裂纹与气孔,其强化相主要为(Co,W)_3C、Cr_(23)C_6、Cr_7C_3和Co_3Mo。熔覆层的平均显微硬度约为624HV_(0.2),较基体提高3倍以上。Co-3的耐擦伤性能明显优于316基体的,在载荷为0~150N的情况下,当划痕长度s≤3.3mm时,擦伤机理主要是塑性变形;当划痕长度3.3mm6.9mm时,擦伤机理主要是裂纹扩展与塑性去除。
The laser cladding of Stellite 3, Stellite 21 and the new Co-based alloy (Co-3) were carried out on the surface of 316 stainless steel. The microstructure and phase composition of the cladding layer were analyzed. The hardness distribution and scratch resistance mechanism were studied. The results show that the microstructure of Co-3 is uniform, compact and free of cracks and pores. The strengthening phases of Co-3 are (Co, W) 3C, Cr 23 C 6, Cr 7 C 3 and Co 3 Mo. The average microhardness of the cladding is about 624HV_ (0.2), more than 3 times higher than that of the matrix. The scratch resistance of Co-3 is obviously better than that of 316 matrix. Under the condition of load of 0 ~ 150N, the scratching mechanism is mainly plastic deformation when the length of scratches is s≤3.3mm. When the length of scratches is 3.3mm < When s≤6.9mm, the mechanism of abrasion is mainly caused by the grain slip and micro-cracks caused by plastic deformation. When the scratch length s> 6.9mm, the mechanism of abrasion is mainly crack propagation and plastic removal.