复合涂层激光熔池温度场及流场的数值模拟

建立了复合涂层激光熔池三维准稳态流场及温度场的数值模型,计算出熔池温度分布和速度分布及几何形状。分析了激光功率对熔池温度场、流场及形状的影响。计算结果表明,对于厚度为0.08mm的Ti-Al(30%)复合涂层系统,功率为750W时,复合涂层没有熔化,但Al基材产生熔化;功率为1400W时,在不同材料层内形成上下两个分离的熔池。复合涂层先熔化还是Al基材先熔化,依赖复合涂层厚度。激光重熔实验确认了分离熔池的存在,同时计算结果和实验结果基本吻合。

A numerical simulation for three dimensional quasi-state fluid flow field and temperature field in molten pool for composite coating system

A three dimensional quasi-state numerical model of fluid flow,heat transfer process in the melted pool for composite coating was developed,and the temperature profile,velocity profile in laser pool and pool geometry were successfully calculated. Affects of laser power on heat transfer and fluid flow in a laser pool and the pool geometry were investigated. Numerical results show that there is only one pool in the substrate when laser power is 750W,and there are two separated pools when laser power is 1400W for the composite coating system of Ti-Al(30%) alloy. It is decided by the thickness of the composite coating,whether the composite coating firstly is melt or Al substrate. The experiment of laser remelting was performed for composite coating system,the separated pools have been observed,and the pool geometry was agreement with that calculated.