超声功率对激光熔覆WC强化Fe基复合涂层组织与性能的影响

Effect of ultrasonic power on microstructure and properties of laser-clad WC strengthened Fe-based composite coating

选用激光作为热源,在45钢基体上激光扫描熔覆制备WC颗粒增强涂层,同时采用金相光学显微镜（OM）、扫描电镜（SEM）、X射线衍射仪（XRD）以及磨粒磨损试验机等实验仪器设备,测试分析了超声波功率对所制备涂层试样的显微组织大小与耐磨损性能的影响。此外,选用分析软件Image-Pro Plus对涂层WC晶粒大小进行测量和计算。结果表明：空化效应以及声流作用跟随超声波功率升高而变得愈加剧烈,对涂层组织的细化能力随之提高,但当超声波功率超过1000 W时,继续增加超声波功率,细化能力提升缓慢。WC颗粒大小则从84μm细化到10.6μm。涂层硬度与相对耐磨性均呈相同的变化规律,即呈先快速升高后缓慢升高的趋势。其中当超声波功率提高到1250 W时,WC颗粒平均尺寸为10.6μm,样品涂层宏观硬度高达63.5 HRC,其耐磨损性能则约为45钢的27倍。

The in situ synthesized WC-Fe composite were prepared on 45 steel by laser cladding. Effect of ultrasonic power on the microstructure and properties was investigated through optical microscopy, SEM, XRD and MLS-23 wet sand rubber wheel tester.Meanwhile,the grain size was measured and calculated by the Image-Pro Plus software. The results show that the cavitation and acoustic stream effects become stronger with the increase of ultrasonic power,which leads to the increase of the refinement ability of the coating;however,the refinement ability increases slower when the ultrasonic power becomes lager than 1000 W. With the increase of ultrasonic power,the grain size reduces from 84 μm to 10. 6 μm. The hardness and relative wear resistance increase first and then lowly. When the ultrasonic power is 1250 W,the average grain size is 10. 6 μm,the hardness is 63. 5 HRC,and the wear resistance of the coatings is about27 times than that of the substrate.