温度对CT20合金孪生变形行为的影响

Influence of temperature on twinning deformation behavior of CT20 alloy

在不同温度(20～300 K)下对CT20钛合金的拉伸变形行为进行研究,并采用金相显微镜、SEM和TEM观察变形组织及断口,揭示温度对CT20孪生变形行为的影响规律。结果表明,随温度降低,CT20合金的抗拉强度提高,伸长率下降,拉伸断口的颈缩程度逐渐减小;220 K的变形组织内出现孪晶,且孪晶数量和尺寸随温度降低均有所增加;300 K温度下合金的拉伸变形以位错滑移为主导,220 K和20 K下为滑移和孪生共同作用。

The tensile deformation behavior of titanium alloy CT20 under different temperatures（20-300 K） were investigated.The deformation microstructure and fracture were observed by metallographic technology,SEM and TEM.The influence law of temperature on the deformation behavior of the alloy was revealed.The results show that the tensile strength of CT20 alloy increases with temperature decreasing,but the elongation and the necking degree of tensile fracture decrease.At 220 K,twin crystals appear in the deformation structure,the size and number of twin grains increase somehow with deformation temperature decreasing.Dislocation slip mechanism dominates the deformation under 300 K while both slip and twinning acts deformation under 220 K and 20 K.