磁场辅助激光沉积涂层微观组织与性能研究

Microstructure and properties of laser deposition coating assisted by magnetic field

为了改善激光沉积过程中,涂层出现气孔、裂纹与基材结合不良等缺陷,采用旋转磁场辅助激光沉积的方法,在304奥氏体不锈钢制备了Fe106+镍包碳化钨(质量分数为0.05)复合涂层。借助扫描电子显微镜、X射线衍射仪、激光共聚焦扫描显微镜等表征手段进行了组织结构和物相分析,通过硬度计、摩擦磨损试验机对其耐磨性进行测定。结果表明,旋转磁场可以抑制熔池流动,促进了涂层组织细晶强化和匀质效应;磁场强度为70mT时涂层显微硬度是无磁场涂层的1.16倍;相同的磨损条件下,磁场强度为70mT的涂层比无磁场涂层失重降低了64.2%,耐磨性得到明显改善。利用磁场辅助激光沉积对改善激光沉积缺陷是有帮助的。

In order to improve coating defects such as porosity,crack and poor bonding with substrate during laser deposition,Fe106+nickel-coated tungsten carbide(mass fraction of 0.05)composite coating was prepared on 304 austenitic stainless steel by the method of laser deposition assisted by rotating magnetic field.The microstructures and phase composition of the coating were analyzed by means of scanning electron microscope,X-ray diffraction and confocal laser scanning microscope.The wear resistance of the coating was studied by means of hardness tester and friction wear tester.The results indicate that the rotating magnetic field can inhibit the flow of molten pool and promote the fine grain strengthening and homogenization of the coating microstructure.The microhardness of the coating with magnetic field strength of 70mT is 1.16 times that without magnetic field strength.Under the same wear condition,the weight loss of the coating with magnetic field strength of 70mT is 64.2%lower than that of the coating without magnetic field.The wear resistance is obviously improved.laser deposition assisted by magnetic field is helpful to improve laser deposition defects.