ABSTRACT

Ni204 cladding layers were prepared on the surface of 45# steel alloys via laser cladding under different overlap modes. The effects of overlap modes on microstructure evolution, microhardness, wear resistance, compressive and tensile strength were investigated. The intensity of the diffraction peaks is related to the cladding strategy. The remelting mode introduced by “double vertical cross” reduces the cooling rate and improves the uniformity of microstructure, exhibiting a stability of the microhardness and wear resistance. Cr_0.19Fe_0.7Ni_0.11, [Fe, Ni], and Ni–Cr–Nb–Mo are primary detected phases in the cladding layer. With the increase in overlap uniformity, the content of [Nb, Mo] which precipitated in grain boundary increases and the microstructure is refined. The uniform microstructure distribution promotes the stable distribution of microhardness and friction coefficient. The angle between the extension direction of the overlap area and the applied loading directly determines the performance of the Ni204 alloy after yielding. The inter-laminar overlap mode weakens the effect of shear stress induced by microstructure differences.

摘要

采用激光熔覆不同搭接方式在45#钢合金表面制备Ni2O4熔覆层。研究了重叠模式对显微组织演变、显微硬度、耐磨性、压缩和拉伸强度的影响。衍射峰的强度与包层策略有关。“双纵横”引入的重熔模式降低了冷却速度，提高了组织的均匀性，显微硬度和耐磨性保持稳定。铬_0.19铁_0.7镍_0.11、[Fe, Ni] 和 Ni-Cr-Nb-Mo 是熔覆层中检测到的主要相。随着重叠均匀度的增加，晶界析出的[Nb，Mo]含量增加，组织细化。均匀的微观结构分布促进了显微硬度和摩擦系数的稳定分布。重叠区的延伸方向与外加载荷的夹角直接决定了Ni2O4合金屈服后的性能。层间重叠模式减弱了由微观结构差异引起的剪切应力的影响。