(西北有色金属研究院，西安 710016)
摘 要: 在不同应变速率下对CT20钛合金的拉伸变形行为进行研究，并采用SEM和TEM等方法观察应变组织及断口形貌，揭示应变速率对CT20孪生变形行为的影响规律。结果表明：在300 K温度下，应变速率的提高使CT20合金的强度提高，延伸率降低；在20 K下，应变速率提高，使CT20合金的强度和延伸率均下降。在温度为300 K、应变速率高于6.67×10-1 s-1和温度为20 K、应变速率低于6.67×10-3 s-1的条件下，CT20合金的变形均为滑移和孪生共同作用。在温度为20 K下，当CT20合金拉伸应变速率超过6.67×10-3 s-1时，孪生变形受到抑制，材料的延伸率迅速降低。
关键字: CT20；钛合金；孪生；应变速率；拉伸
（Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China）
Abstract:The tensile deformation behavior of titanium alloy CT20 under different strain rates was investigated. The deformation microstructure was observed and analyzed by SEM, TEM and metallographic technology. The influence of different strain rates on the alloy deformation behavior and the relations between twinning and mechanical properties were revealed. The results show that, with strain rate increasing, the strength increases but elongation decreases at 300 K, while both the strength and elongation reduce at 20 K. CT20 keeps a good plasticity because both slip and twins dominate in the deformation at strain rate of 6.67×10-1 s-1, 300 K and strain rate lower than 6.67×10-1 s-1, 20 K, respectively. At strain rate above 6.67×10-1 s-1 and 20 K, the elongation of CT20 decreases directly and the fractures are brittle because both low temperature and high strain rate keep the twins from influencing deformation.
Key words: CT20 titanium alloy; twin; strain rate; tensile
