表面预处理对超音速激光沉积Ti6Al4V涂层界面结合的影响(特邀)

Effect of Surface Pretreatment on Interfacial Bonding of Ti6Al4V Coating Prepared by Supersonic Laser Deposition(Invited)

以Ti6Al4V沉积层为基体,研究基体表面预处理对超音速激光沉积涂层/基体界面结合的影响。试验前,基体表面经过三种不同方式的预处理,分别为抛光、打磨和喷砂。利用X射线衍射仪和表面轮廓仪对基体表面的物相组成和粗糙度进行了分析,利用光学显微镜对涂层/基体界面结合进行了分析,利用单颗粒撞击有限元模型对颗粒与不同表面粗糙度基体的结合情况进行了分析。研究结果表明,打磨处理的基体由于表面生成氧化钛陶瓷相,涂层发生脱落。抛光处理的基体较喷砂处理的基体有更低的表面粗糙度,其涂层/基体界面结合更紧密。数值模拟表明,基体表面的起伏特征在颗粒/基体界面处促成温度和应变的不均匀分布,阻碍颗粒与基体间的紧密结合。

This study is focused on the investigation of the effect of substrate surface pretreatment on the interfacial bonding between a Ti6Al4V coating,prepared by supersonic laser deposition,and a substrate.Prior to the deposition,the substrate surface is pretreated by three different methods,namely polishing,grinding,and sand blasting.The phase composition and roughness of the substrate surface are analyzed using an X-ray diffractometer and a surface profilometer,respectively.An optical microscope is employed to analyze the interfacial bonding between the coating and substrate,while the bonding characteristics between the particles and substrates with different surface roughness,is numerically evaluated using a finite element model based on single particle impact.The results indicate that the coating detaches from the substrate treated by grinding owing to the formation of titanium-oxide ceramic phases on the substrate surface.However,the surface roughness of the polished substrate is lower than that of the sand blasted one,and thus,the coating/polished substrate interface is more tightly bonded.The numerical simulation results demonstrate that because of the undulating characteristics of the substrate surface,the particle/substrate interface shows inhomogeneous temperature and strain distributions,which prevent close bonding between the particles and substrates.