成形气氛中氧含量对激光沉积TA15钛合金组织及力学性能的影响

Effects of Oxygen Content in the Argon Shielding Gas on Microstructure and Mechanical Properties of Laser Deposition Manufacturing TA15 titanium alloy

摘要:

采用激光沉积制造方法制备了TA15钛合金厚壁件,通过光学显微镜(OM)和扫描电子显微镜(SEM)对其显微组织、断口及力学性能进行分析,研究成形气氛中氧含量对激光沉积TA15钛合金组织及力学性能的影响。结果表明：随着气氛中氧含量增加,沉积态和退火态试样的显微组织均为典型网篮组织无明显变化。退火态试样的室温拉伸强度提高而塑性下降,氧含量保持在5×10^-5以下能获得较好的综合力学性能。退火态试样的显微硬度低于沉积态且两者均随氧含量增加逐渐提高。室温拉伸断口的断裂机制随着氧含量增加由韧性断裂变化为半解理半韧性断裂。

Abstract:

The TA15 titanium alloy specimens were prepared by laser deposition manufacturing. The effects of oxygen content in the argon shielding gas on microstructure, fracture and mechanical properties of laser deposition manufacturing TA15 titanium alloy have been investigated by optical microstructure (OM) and scanning electron microscopy (SEM). The results show that both as-deposited and annealed specimens microstructure are typically basket-weave microstructure without dramatic changes with the increasing of the oxygen content of the atmosphere. The tensile strength at room temperature of the annealed alloy is gradually on the rise while the ductility is decreasing. By considering both the ductility and strength properties, samples with the oxygen content at 0~5×10^-5 have the best comprehensive mechanical properties. Microhardness of the annealed samples is lower than that of the as-deposited, and they are gradually enhancing with the increasing of oxygen content. Room temperature tensile fracture mechanism changes from ductile fracture to semi-cleavage and semi-ductile fracture with the increasing of oxygen content.