为了研究激光重熔工艺参数对等离子体喷涂复合陶瓷涂层组织结构的影响, 根据激光重熔的特点, 采用ANSYS有限元软件的参数化设计语言, 建立了TiAl合金表面激光重熔等离子体喷涂Al2O3-13%TiO2（质量分数）复合陶瓷涂层连续移动三维温度场有限元模型, 对激光重熔温度场进行了分析。分析结果表明,当陶瓷涂层厚度较大时, 受到陶瓷材料导热系数较低的影响, 激光重熔时无法使整个陶瓷层实现完全重熔, 根据重熔时作用区温度场分布, 可将整个涂层分为重熔区、烧结区和残余等离子体喷涂区; 在优化的工艺参数下, 采用相对较低的激光重熔功率和较低的扫描速度能够获得厚度较大的重熔区和烧结区。实验结果表明,重熔后的陶瓷涂层形成了晶粒细小且致密的等轴晶重熔区、烧结区和片层状残余等离子体喷涂区, 并且重熔区和烧结区厚度的计算值和实验值吻合较好。

In order to study the effects of laser remelting on microstructure of composite ceramic coating prepared by plasma spraying, in view of the characteristics of laser remelting, a finite element model for analyzing the transient temperature field of three-dimensional moving laser remelting Al2O3-13%TiO2 （mass fraction）composite ceramic coating prepared by plasma spraying was established by using the employment of ANSYS parametric design language. The temperature field in the coating and substrate was analyzed. The results show that the ceramic coating cannot be total remelted due to low conductivity of ceramic when the coating is thick enough. According to the distribution of temperature field, the coating can be divided into the remelted zone, the sintered zone and the remained plasma-sprayed zone. The thickness of the remelted zone and the sintered zone is larger using a lower laser power and scanning speed under optimum parameters. The experimental results show that the composite ceramic coating forms three different zones after laser remelting, i.e. the remelted zone (fine equiaxed grains structure), the sintered zone and remained plasma-sprayed zone (lamellar-like structure). The obtained experimental results show a good agreement with the simulation results, which indicates that the established numerical model is correct and reliable.