中文摘要：

采用等离子堆焊技术在304L不锈钢表面上堆焊碳化钨颗粒增强镍基合金层。研究了不同碳化钨颗粒含量对堆焊层组织形态、显微硬度的影响。结果表明,堆焊层组织包括树枝晶和枝晶间多元共晶组织;堆焊层中初始碳化钨颗粒沉积在堆焊层底部,堆焊层顶部无碳化钨区域出现新的鱼骨状和块状结构。在堆焊过程中,碳化钨颗粒发生熔解并与镍基合金元素相互作用形成低熔点共晶组织,以块状和长片状析出。随碳化钨含量增加,堆焊层平均硬度增加,堆焊层顶部鱼骨状和块状结构对堆焊层硬度没有影响。

英文摘要：

The nickel alloy powder reinforced by tungsten carbide particles was deposited on the surface of 304L stainless steel by plasma transferred arc welding（PTAW）.Effects of tungsten carbides contents on microstructure and microhardness were investigated.The results show that the coatings consist mainly of dendrites of γ-nickel solid solution phases and eutectic mixture as interdendritic constituents,primary tungsten carbides accumulate near the interface and herringbone and block structures are severally found near the surface where is free of tungsten carbides in the coatings reinforced by tungsten carbides.In the process,primary tungsten carbide particles dissolve and react with the elements of nickel-based alloys to form low melting eutectics,which precipitate in the shape of bulk and long flake.With the increase of tungsten carbide content,the average microhardness of the coatings increases.The hardness of coatings is not affected by the herringbone and block structures near the surface.