在300 K及20 K、不同应变速率下对CT20钛合金板材进行单向拉伸，利用扫描电镜、透射电镜等观察拉伸应变组织及断口形貌，揭示了应变速率对CT20钛合金孪生变形行为的影响规律。结果表明：在300 K下，应变速率的提高使CT20钛合金板材的强度提高，延伸率降低；20 K下，应变速率的提高使CT20钛合金板材的强度和延伸率均下降。在300 K、应变速率高于6.67×10－1 s－1和20 K、应变速率低于6.67×10－3 s－1的条件下， CT20钛合金板材的变形均为滑移和孪生共同作用。20 K下， CT20钛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。
The tensile deformation behavior of CT20 titanium alloy plate under different strain rates at 300 K and 20 K was investigated.The deformation microstructures and fracture morphologies were observed by scanning electron micro-scope ( SEM) and transmission electron microscope ( TEM) .The influence of strain rate on twinning deformation be-havior was revealed.The results show that, with strain rate accretion, the strength increases but elongation decreases at 300 K, while both the strength and elongation get reduction at 20 K.Both slip and twins dominat in the CT20 titani-um alloy plate deformation with a strain rate higher than 6.67 ×10 -1 s-1 at 300 K and with a strain rate lower than 6.67 ×10 -3 s-1 at 20 K.When tensile test is conducted with a strain rate above 6.67 ×10 -3 s-1 at 20 K, the elonga-tion of CT20 titanium alloy decreases directly because the twins are restrained.
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