Materials Science and Engineering: A ( IF 6.4 ) Pub Date : 2021-01-16 , DOI: 10.1016/j.msea.2021.140779 Bin Sun , Kuishan Sun , Xianglong Meng , Zhiyong Gao , Wei Cai
Microstructure evolution, texture and shape memory properties of the martensitic Ti−16Nb (at.%) alloy subjected to cold rolling and post deformation annealing were investigated by transmission electron microscopy (TEM), electron backscattered diffraction (EBSD) and Schmid factor analyses. The present alloy deforms mainly by twinning of the type I or its conjugate, the type II twins along with slip of martensite, when cold-rolled in martensite state. The texture of the ex-β grains, in which parallel martensite plates with the type I or the type II twin relation grow, are formed after post-deformation annealing at 700 °C for 30 min. The orientation effect of texture on the Ti−16Nb alloy is analyzed. Both experimental results based on tensile tests and theoretical Schmid factor analysis converge satisfactorily. In result the critical stress for reorientation of martensite variants decreases first, and increases then, as the deviation angle increases. Schmid factor for martensite slip decreases remarkably in the textured Ti−16Nb alloy while the loading direction is parallel to the rolling direction. As a result, slip is introduced difficultly in such case and a total recovery strain of 5% is obtained.
中文翻译:
织构对Ti-16Nb高温形状记忆合金形状记忆性能的影响
通过透射电子显微镜(TEM),电子背散射衍射(EBSD)和施密特(Schmid)因子分析研究了经过冷轧和变形后退火的马氏体Ti-16Nb(at。%)合金的组织演变,织构和形状记忆性能。本合金主要通过孪晶的变形而变形。 I型或其结合物 在马氏体状态下冷轧时,II型孪晶与马氏体滑移。的 β晶粒的织构,其中平行的马氏体板与 输入I或 II型孪生关系生长,是在700°C下进行30分钟变形后退火后形成的。的定向作用分析了Ti-16Nb合金的织构。基于拉伸试验的实验结果和理论Schmid因子分析均令人满意地收敛。结果,当偏离角增加时,用于重新取向马氏体的临界应力首先减小,然后增加。当加载方向与轧制方向平行时,织构的Ti-16Nb合金中马氏体滑移的Schmid因子显着降低。结果,在这种情况下很难引入滑移,并且获得了5%的总恢复应变。