Continuous and uniform laser surface alloying coatings were prepared on 45Mn2 medium-carbon steel substrates previously coated with WC powder layers with different thicknesses. The effect of thickness of pre-coated WC layer on the microstructure, microhardness, and wear resistance of laser surface alloying coating was studied. The laser surface alloying coating was mainly composed of dendrite and ledeburite phases. Not only the WC content in laser surface alloying coating but also its microhardness and wear resistance could be enhanced by increasing the thickness of pre-coated WC layer. However, the cracking problem of alloying coating became worse. The laser surface alloying coating obtained with a 0.24 mm-thick pre-coated WC layer had a microhardness of 715 HV and good wear resistance.%先在 45Mn2 钢上涂覆得到不同厚度的 WC 粉末预制层,再通过激光加工得到连续、均匀的激光表面合金化层.研究了WC 预制层厚度对激光表面合金化层组织结构、显微硬度和耐磨性的影响.所得激光表面合金化层主要由树枝状相和莱氏体组织构成.加厚WC预制层不仅能提高激光表面合金化层中WC颗粒的含量,而且能提高合金化层的显微硬度和耐磨性,但也引起合金化层的开裂加重.当WC粉末预制层的厚度为0.24 mm时,所得激光表面合金化层的显微硬度较高(715 HV),耐磨性也较好.
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