NbC对激光熔覆316L不锈钢组织及性能的影响

Effect of NbC on Microstructure and Properties of Laser-Cladding 316LStainless Steel

为提高316L激光熔覆层的硬度及耐磨性,采用激光熔覆技术在车用304不锈钢表面制备10%(质量分数)NbC/316L不锈钢复合涂层。分别研究复合涂层的组织形貌、相组成、元素分布、硬度及磨损行为。结果表明,复合涂层表面无裂纹、气孔等缺陷,组织均匀致密。涂层由γ-Fe和NbC组成,其中NbC均匀弥散地分布在涂层中。结合涂层微观组织及元素分布,NbC在涂层中起到了细晶强化和第二相强化作用,复合涂层的显微硬度约为354 HV,显著高于316L涂层的显微硬度(233 HV)。由于显微硬度的提高,复合涂层的摩擦系数和磨损率均有降低,复合涂层的平均摩擦系数约为0.387,磨损率为1.41×10^(-5) N·m,约为316L涂层的50%。添加NbC可显著提升316L涂层的硬度和耐磨性。

To enhance the microhardness and wear resistance of 316Lcoatings,NbC/316Lstainless steel composite coatings were synthesized on 304stainless steel substrates using laser cladding.The microstructure,phase composition,element distribution,hardness and wear behavior of the composite coatings were studied,respectively.The results showed that the surface of the composite coating had no defects such as cracks and pores,and the structure were uniform and dense.The coating consisted ofγ-Fe and NbC,where NbC were uniformly and diffusely distributed throughout the coating.Combined with the microstructure and element distribution of the coating,NbC played a fine crystal strengthening and second phase strengthening in the coating,and the microhardness of the composite coating were about 354HV,which was significantly higher than the microhardness of the 316Lcoating(233HV).Due to the improvement of microhardness,the friction coefficient and wear rate of the composite coating have been reduced,and the average friction coefficient of the composite coating was about 0.387,and the wear rate was 1.41×10^(-5)(N·m),which is about 0.5times that of the 316Lcoating.The addition of NbC can significantly improve the hardness and wear resistance of the 316Lcoating.