摘要
再现大型结构件实际成形热过程,研究了激光熔化沉积TC11钛合金的组织特征与力学性能。结果表明,沉积态试样的粗大柱状晶内α+β网篮组织比等轴晶内的更均匀、细小,等轴晶内分布有大片α集束区,晶界处产生了大量连续α相;由于后续沉积层对已沉积层的表层重熔及热处理效应,层间过渡区产生了明显的α相粗化,α相比例增加,因此沉积态试样的室温力学性能各向异性显著。经过950℃保温1 h和550℃保温2 h的双重退火后,退火态试样晶界处的连续α相几乎完全破碎,α+β网篮组织分布更加均匀,室温力学性能各向异性完全消除,塑性大幅增强,综合力学性能基本与锻造态的一致。
The microstructural characteristics and mechanical properties of laser melting deposited TC11 titanium alloys are investigated by the reappearance of actual forming thermal process of large structural parts. The results show that, the α+β basket-weave microstructures in the coarse columnar grains of the as-deposited samples are more uniform and finer than those in the equiaxed grains. The large α colonies are found in the equiaxed grains and there are a lot of continuous α phases on the grain boundaries. Due to the interlayer surface remelting redeposition and annealing effects, the obvious coarsening of α phases occurs in the interlayer transition zone of as-deposited samples and the α phase proportion increases. As a result, the mechanical properties of as-deposited samples at room temperature exhibit an obvious anisotropy. After the double annealing under the schedules of 950 ℃, heat preservation for 1 h and 550 ℃, heat preservation for 2 h, the continuous α phases are nearly broken completely on the grain boundaries of the annealed samples, and the α+β basket-weave microstructures show a more uniform distribution. The anisotropy of the mechanical properties at room temperature is eliminated completely and the plasticity enhances considerably. The comprehensive mechanical properties are basically at the same level as those of the forged samples.
作者
周庆军
严振宇
韩旭
宋全
刘京威
王福德
Zhou Qingjun;Yan Zhenyu;Han Xu;Song Quan;Liu Jingwei;Wang Fude(Capital Aerospace Machinery Co.,Ltd.,Beijing 100076,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2018年第11期61-68,共8页
Chinese Journal of Lasers
关键词
激光技术
激光熔化沉积
钛合金
组织特征
力学性能
laser technique
laser melting deposition
titanium alloy
microstructure characteristics
mechanical properties
