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研究了3种热处理制度及激光多道搭接对激光熔化沉积TC18钛合金显微组织的影响。结果表明:按照去应力退火-等温退火-双重退火的顺序,晶界α和晶内α片层都逐渐粗化,大柱状晶逐渐分裂,小晶粒逐渐趋于等轴化;激光扫描搭接区域,温度梯度大,重熔间隔时间短,生成大柱状晶;非搭接区域温度梯度较小,重熔间隔时间长,难以满足柱状晶外延生长的条件,从而形成小晶粒带。
The effects of three heat treatment systems and laser lap lapping on the microstructure of laser-melted Ti alloy TC18 were studied. The results show that the grain boundary α and the intragranular α lamellae are gradually roughened, the large lamellae are gradually split and the small ones are gradually equiaxed, according to the order of stress-relief annealing-isothermal annealing-double annealing. Laser scanning lap Large temperature gradient and short remelting interval lead to the formation of large columnar crystals. The temperature gradient in the non-lapped zone is small and the remelting interval is long, which makes it difficult to meet the conditions of columnar epitaxial growth.