热处理对激光快速成形TC21钛合金组织和硬度的影响

采用激光快速成形技术制备出TC21钛合金块状坯料,研究了去应力退火及固溶时效热处理对成形件组织和硬度的影响。结果表明:去应力退火后,成形件组织和显微硬度基本无变化;固溶+时效热处理后,原沉积态明暗两区统一,硬度基本无差别,表明组织已均匀化。随着固溶温度的升高,网篮组织中的α片变宽,球状α相的数量增多,晶界α相发生粗化。当固溶温度为932℃时,成形件沉积态中粗大的柱状晶发生再结晶,转变为较细小的等轴晶。

Effect of Heat Treatment on Microstructure and Hardness of Laser Rapid Forming TC21 Alloy

With the aid of laser rapid forming(LRF) technique,the TC21 alloy samples are prepared.From the viewpoint of microhardness and microstructure,the effects of stress relief annealing and solution aging are investigated by the means of modern analyzing and testing analysis.The results show that two different microstructure areas existed in the as deposited TC21 alloy are bright area and dark area.After stress relief annealing,the difference mentioned above is not disappeared.Whereas after solution aging,the difference mentioned above is disappeared.Since the microstructure is homogenized,there is no difference in hardness between the microhardness of bright area and dark area.With the solution temperature rising,the width of α lath,the ratio of globular α and the size of grain boundary α increase.When the temperature rises to 932℃,recrystallization happens and results in equiaxed grains transformed from coarse columnar grains existed in as deposited LRF TC21 alloy.