中文摘要：

采用ANSYS软件“生死单元”技术对45钢表面激光多道熔覆过程进行了数值仿真，并对其温度场进行了分析。结果表明，熔覆过程中基体上各点的温度虽然随时间而有所变化，但是各点以固定的温度随着热源同步向前移动，形成准稳态温度场。采用合金同步法送粉激光熔覆技术，以温度场数值分析结果为依据得到了合适的工艺参数，在45号钢基体表面熔覆Ni60＋20％WC复合粉末，制备出原位析出的颗粒增强金属基复合材料表层，利用金相显微镜、X射线衍射仪对熔覆层金相组织和相结构进行了分析。结果表明，横截面组织由表及里依次为：熔覆区，结合区，热影响区及基体区，熔覆层组织致密，与基体为冶金结合；熔覆层内的WC颗粒分布不均，强化相除外加的WC外，还有金属间化合物FeNi3、BNi3等以及铬的碳化物相Cr23C6,共同组成了抗磨损的主体。

英文摘要：

The numerical simulation and its temperature - field analysis were obtained during the process of multi - path laser cladding on 45 steel＇s surface by birth and death element of ANSYS software. The results show that al- though each point＇s temperature changes as time goes by, quasistationary temperature distribution is formed because the point＇s temperature keeps pace with the heat resource＇s move. Based on alloy synchro delivery method and tem- perature field＇s numerical analysis, the optimum processing parameters were obtained. Through 45 steel＇s surface coating with Ni60 ＋ 20% WC compound powder, particle reinforced metal matrix composite layer was formed and its metallic phase and phase structure of laser cladding layer was analyzed by combining metalloscope with X - Ray Diffractomer. The experiments indicate that the organization about intersecting surface from the surface to the cen- tre contains cladding coating, seam area, heat affected zone and matrix zone, and its structure is very dense, meanwhile the metallurgical bonding is consist of cladding coating and matrix. WC particle is unevenly distributed. Besides the extra WC, the strengthening phase contains Cr23C6 and intermetallic compounds, such as FeNi3 ,BNi3 , ect, which are dominant to wear.