激光搭接再重叠扫描熔覆镍基纳米WC/Co层的显微组织

Microstructure of nickel based nanometer WC/Co coating prepared by laser overlapping and scanning again cladding

采用CO2激光在45钢表面制备镍基纳米WC/Co熔覆层。使用搭接再重叠扫描工艺,突破了单道激光熔覆处理区域较窄的局限性以及搭接熔覆层中的碳化物形态多样性和分布不均匀性较大的缺陷。搭接再重叠扫描层硬度不下降且不出现新的裂纹和孔洞,这使大面积激光熔覆的实际应用成为可能。研究结果表明,搭接再重叠扫描的熔覆层中仍然存在相当数量的粒度≤100nm的碳化物颗粒,其纳米效应对该熔覆层的抗裂止裂起了重要作用。

CO2 laser was adopted to prepare nickel based nanometer WC/Co composite coating on the surface of 45 steel. Laser overlapping and scanning again was used to break the limitation of single channel laser cladding and the defect from the large difference of the carbides in shape and distribution after single overlapping. The results show that the hardness of laser overlapped and scanning again clad coating is not lowered and at the same time no new cracks and pores appear, it makes the practical application of broadened area of laser cladding possible. The composite coating in overlapping and scanning again has a considerable quantity of nanometer carbides particles visible with a granularity ≤ 100 nm ,and its nanometer effect plays an important role in the anti-cracking function.