摘要
The microstructure, microhardness and tensile properties of laser additive manufactured (LAM) Ti?5Al?2Sn?2Zr?4Mo?4Cr alloy were investigated. The result shows that the microstructure evolution is strongly affected by the thermal history of LAM process. Primary α (αp) with different morphologies, secondary α (αs) and martensite α' can be observed at different positions of the LAMed specimen. Annealing treatment can promote the precipitation of rib-like α phase or acicular α phase. As a result, it can increase or decrease the microhardness. The as-deposited L-direction and T-direction specimens contain the same phase constituent with different morphologies. The tensile properties of the as-deposited LAMed specimens are characterized of anisotropy. The L-direction specimen shows the character of low strength but high ductility when compared with the T-direction specimen. After annealing treatment, the strength of L-direction specimen increases significantly while the ductility reduces. The strength of the annealed T-direction specimen changes little, however, the ductility reduces nearly by 50%.
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%。
基金
Projects(51105311,51475380)supported by the National Natural Science Foundation of China
Project(2013AA031103)supported by the National High-Tech Research and Development Program of China
