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研究激光增材制造Ti-5Al-2Sn-2Zr-4Mo-4Cr合金的显微组织演化、维氏硬度及室温拉伸性能。结果表明:激光增材制造过程的热历史显著影响显微组织演化。在试样的不同沉积高度位置可以观察到不同形貌的初生α相、细小次生α相及马氏体相。退火处理可以促使短棒状α相或细小次生α相析出,从而降低或增加维氏硬度。L方向和T方向拉伸试样相组成相同但形貌不同。沉积态试样室温拉伸时表现出明显的各向异性。L方向拉伸试样的强度低但塑性好,T方向拉伸试样相反。经退火处理之后,L方向拉伸试样的强度增加但塑性显著降低;T方向拉伸试样的强度无明显变化而塑性降低50%。
The microstructure evolution, Vickers hardness and tensile properties at room temperature of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy were studied by laser additive manufacturing. The results show that the thermal history of the laser additive manufacturing process significantly affects the microstructure evolution. Different morphologies of primary α phase, fine secondary α phase and martensite phase can be observed at different depositional height of the sample. Annealing treatment can promote the short rod α phase or fine secondary α phase precipitation, thereby reducing or increasing the Vickers hardness. L-direction and T-direction tensile specimens with the same phase composition but different morphology. The as-deposited samples show obvious anisotropy when stretched at room temperature. Tensile specimens in the L direction have low strength but good ductility and T-direction tensile specimens. After annealing, the tensile strength in L direction increased but the plasticity decreased significantly. The tensile strength in T direction did not change obviously and the plasticity decreased by 50%.