显微组织对BT22钛合金棒材力学性能的影响

Effect of Microstructure on Mechanical Properties of BT22 Titanium Alloy Bar

采用4种工艺方案制备了不同组织类型的BT22钛合金棒材,通过测试其显微组织、室温及高温力学性能,研究其间相关关系。结果表明,按魏氏、网篮、双态、等轴这一组织形态顺序,对应的室温及高温拉伸强度值递减,塑性(δ、ψ)随之递增,尤其面缩值增加较为明显,断裂韧性值递减,冲击韧性变化不明显。等轴组织对应的室温拉伸强度较低,虽达到标准要求,但已接近指标下限,富余度不大,且断裂韧性值偏低;魏氏组织的断裂韧性及强度明显高于其它组织形态,但塑性明显降低,达不到标准要求;网篮及双态组织对应的性能均达到标准要求,具有较好的强度与塑性的匹配,综合力学性能较好。

Using 4 kinds of technique program, the titanium alloy bars BT22 with different type of structure was prepared, and the mechanical properties at room and high temperature and the microstructure of the alloy were tested. The results show that in the order of widmanst tten structure, net structure, binary-state structure, equal-axed structure, the corresponding toughness and tensile strength at room temperature and high temperature reduced step by step, and the plasticity（δ, φ） raised gradually with it, especially the fracture shrinkage raised obviously, and the impact toughness changed slightly. The tensile strength at room temperature for the Bt22 with equal-axed structure was lower, though it can meet the specification, but near the lower limit of the index, and the toughness is some lower. The toughness and strength of the specimen with widmanstatten structure was obviously higher than that with other structure, but the plasticity was much lower, which can not meet the specification. The performance of the alloy with the net structure and binary-state structure can meet the specifications and the strength matched plasticity well, the comprehensive mechanical properties were better.