交变磁场对激光熔覆Fe基复合涂层组织结构及其耐磨性的影响  

Influence of AC Magnetic Field on Microstructure and Wear Behaviors of Laser Cladding Fe-Based Composite Coating

作　　者：蔡川雄[1] 刘洪喜[1] 蒋业华[1] 王传琦[1] 张晓伟[1] 唐淑君[1] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093

出　　处：《摩擦学学报》2013年第3期229-235,共7页Tribology

基　　金：国家自然科学基金项目(51165015)资助~~

摘　　要：采用激光熔覆辅助电磁控制工艺在45钢表面合成了Fe-Cr-Si-B-C复合涂层.通过对熔覆层进行SEM、EDS和XRD表征,研究了外加交变磁场对涂层微观组织和物相结构的影响.结果表明:外加磁场可降低激光熔池固-液界面前沿液相的温度梯度和增加非均质形核率,促使粗大、方向性很强的柱状晶转变为均匀、细小的等轴晶,并能够消除熔覆层内的气孔和裂纹等缺陷,但其对熔覆层物相组成的影响不大.熔覆涂层由白色初生γ-(Fe,Cr)固溶体相和其间黑色的γ-(Fe,Cr)共晶相组成,同时含有少量Fe3(B,C)、Cr7(B,C)3、CrFeB等碳化物和硼化物.常温干摩擦磨损试验表明,外加磁场所制备的涂层耐磨性能得到明显提高,其磨损失重仅为未加磁场的43%,且摩擦系数波动较小.Fe - Cr - Si - B - C composite coatings were fabricated on 45 medium carbon steel substrate using electromagnetic control assisted laser cladding process. The microstructure, phase composition, friction and wear behaviors of the composite coatings were investigated by X - ray diffraction, scanning electron microscopy, energy dispersespectroscopy, and a pin - on - disc tribometer. The results indicate that AC magnetic field can reduce the liquid phase temperature gradient of laser molten pool solid - liquid interface and increase the heterogeneous nucleation rate. Consequently, coarse columnar grains into uniform and fine equiaxed grains was prompted and the pores and cracks defects in the composite coatings were eliminated. However, it had no distinct effect on the phase composition of the composite coatings. The coatings were mainly composed of ＂y - （ Fe, Cr） solid solution, ~/- （ Fe, Cr） eutectic and a small amount of Fe3 （ B, C ） , Cr7 （ B, C） 3 and CrFeB compounds. The friction and wear behaviors of the composite coatings treated by AC magnetic field were much better than that of untreated coatings. The wear of the electromagnetic control assisted laser cladding coatings was 50% of that of the non - magnetic field coatings, and the fluctuation of friction coefficient was low.

关 键 词：激光熔覆 交变磁场 复合涂层 微观组织 摩擦磨损 

分 类 号：TN249[电子电信—物理电子学]