高频感应辅助激光熔覆MCrAlY涂层的微观组织及其抗氧化性能

利用高频感应辅助激光熔覆技术在镍基高温合金表面制备了MCrAlY涂层,与激光直接熔覆制备的MCrAlY涂层进行对比研究。采用扫描显微镜、X射线衍射仪及能谱仪对涂层的微观形貌和组织结构进行了分析。结果表明,在高频感应辅助的作用下,涂层的温度场发生了改变,温度梯度降低,涂层中的Al元素有充分的时间上浮,在涂层表面形成了大量的Al2O3陶瓷相,使得涂层的抗氧化性能明显提高。同时,涂层的横截面呈现网状结构,其主相仍以γ-NiCo相为主,而Y元素在黑色区域为富集形态,可以净化晶界,减少由晶界产生内应力,改善涂层的成型性能。

Microstructure and Anti Oxidation of MCrAlY Coating by High-Frequency Induction Aided Laser Cladding

MCrAlY coating on the Ni-base superalloy surface by the high frequency induction assisted with laser cladding technology is compared with MCrAlY coating on the Ni-base superalloy surface directly by laser cladding.The micro-morphology and composition of the laser sintered samples are characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD).The results show that the temperature field of the MCrAlY coating is changed by the high-frequency induction.Consquentely,the temperature gradient decreases and the Al element of coating has enough time to float.Finally,a large number of Al2O3ceramics form on the coating surface,thus improveing the coating oxidation.Meanwhile,the cross-section of coating presents a network structure,but the main phase is still γ-NiCo,and the Y element presents an enrichment patterns in the black area.All these can reduce the internal stress generated by the grain boundary and improve the performance of the coating forming.