【作者】 张明义； 钟敏； 袁帅； 柏劲松；

【Author】 Zhang Mingyi;Zhong Min;Yuan Shuai;Bai Jingsong;Institute of Fluid Physics, China Academy of Engineering Physics;

【机构】 中国工程物理研究院流体物理研究所；

【摘要】 本文采用晶体相场模型结合等体积变形方法,模拟了FCC金属中纳米孪晶变形过程,研究了纳米孪晶厚度和预置位错对纳米孪晶变形机制的影响规律,发现在孪晶厚度较小时,纳米孪晶首先在孪晶内部发生变形并导致孪晶内部的非晶化,孪晶界在变形过程中不发生位错形核,而是直接非晶化;在孪晶厚度较大时,孪晶界首先通过形核不全位错,不全位错沿孪晶界滑移导致孪晶界发生迁移,部分孪晶厚度增加,一部分孪晶厚度减少,随着不断的不全位错形核和迁移,导致孪晶界逐步失去共格性,演化为无序晶界,孪晶界附近发生非晶化;在孪晶厚度较高的纳米孪晶中预置初始位错,变形过程中位错首先沿孪晶方法迁移,并导致孪晶界迁移,随后初始位错大量增殖和滑移,使得孪晶界逐渐演化为普通晶界。更多还原

【Abstract】 Based on the phase field crystal model, the deformation process of nano-twin was simulated using Equal volume method, and the effect of thickness of nano-twin and preset dislocation on the deformation mechanism was studied. The results demonstrated that when the thickness of nano-twin is small, the deformation happened at the inside of nano-twin first and no dislocation nucleated at the twin boundary, the nano-twin became amorphization. When the thickness of nano-twin is big, partial dislocation can be nucleated at the twin boundary first and then glide along the twin boundary, resulting in the migration of twin boundary. The thickness of nano-twin changes and amorphization followed by the nucleation and emission of large amount partial dislocation. The loss of coherence in twin boundaries transformed them into incoherent grain boundraies. The preset of dislocation at twin boundary accelerate the amophization of nano-twin and the disordering of twin boundaried.更多还原