WC颗粒在堆焊过程中溶解机理的研究

研究了WC／Ni3Al表面强化功能复合材料的制备及WC颗粒的溶解机理。在堆焊过程中，WC／Ni3Al复合材料焊条中的WC直接溶解进入基体中，然后析出W2C，而非WC分解成W2C然后溶解。当焊条中含5％(质量分数)WC时，部分Al被氧化，WC溶解，析出W2C，形成碳化物包裹氧化物的球形复合析出物，基体转化成Nb(AlTi)C，形成碳化物包裹氧化物／金属间化合物的复合材料。随着WC含量增加，Al氧化减少。当焊条中的WC含量达到30％时，焊层中的Al不被氧化，表面层中的大部分WC颗粒溶解，析出针状W2C，形成碳化物／金属间化合物复合材料，耐磨性可达45钢的3倍以上。

Dissolving behavior of WC particles in lap welding

Fabrication process of WC/Ni3 Al composites and dissolving behavior of WC particles in welding were discussed in this paper. Some WC particles in the composite rods of WC/NisAl dissolved into the matrix in welding, and then W2C particles precipitated. When the rods contained only 5wt% WC, partial Al was oxidized and WC transformed into W2C, the matrix transformed into Ni3 (AlTi)C as a result that oxide-embraced-carbide/nickel aluminide composites formed. With WC content in the rods up to 30wt%, no Al was oxidized, and crack-free welding surface was obtained. Most of WC particles in the surface layer dissolved in welding, and needle-like W2C particles precipitated. The wear resistant ability of the welding composites was three times of the 45 steel.