固溶时效对等离子堆焊WCp/18Ni300钢复合涂层组织与性能的影响

采用等离子堆焊技术在Cr5钢表面制备WC增强18Ni300钢复合涂层. 研究添加质量分数为25%和35%的球形WC对堆焊层组织与性能的影响，分析固溶(900 ℃ × 1 h)和时效(490 ℃ × 5 h)处理前后堆焊层的显微组织/相变过程/显微硬度和摩擦磨损性能. 结果表明，在马氏体时效钢粉末中添加WC颗粒影响堆焊层组织和马氏体相变. WC/MS300复合堆焊涂层的显微组织主要以奥氏体为主. 经固溶时效热处理后，基体试样硬度和摩擦磨损性能下降，而WC/MS300试样中γ-F转变为α-Fe，硬度和耐磨性显著改善，添加35%WC试样耐磨性能最佳. 由WC的微观结构演变表明，固溶时效后WC颗粒周围形成厚的扩散层，显著改善了界面结合.

Effects of solution and ageing treatment on microstructure and properties of WC reinforced 18Ni300 steel substrate composite coatings by plasma transferred arc

WC-reinforced 18Ni300 steel composite coating was prepared on the surface of Cr5 steel by plasma transferred arc. The influence of adding 25% WC and 35% mass fraction of spherical WC on the microstructure and properties were investigated. The microstructure/phase transformation and properties of the surfacing layer before and after solution treatment (900 °C × 1 h) + aging (490 °C × 5 h) were analyzed and compared. The results show that the addition of WC particles in the maraging steel affects the martensitic transformation in the surfacing structure. The microstructure is mainly austenitic in the WC/MS300 composite surfacing coating. After solution aging heat treatment, the microhardness and wear resistance of WC/MS300 composite surfacing coating were significantly improved, and the microstructure transformed from γ-Fe to α-Fe in the sample, 35%WC coating presented best wear resistance. However, the microhardness and friction and wear properties of the substrate samples decreased. The microstructure evolution of WC indicates that a thick diffusion layer is formed around the WC particles after solution aging heat treatment, which significantly improves the interfacial bonding.