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总览 评价 曲绍兴 * , 王贵民 , 周昊飞 , 黄志龙 ( 浙江大学应用力学所; ) 摘要: 实验发现带有初始缺陷的纳米孪晶界很容易成为位错源发射位错。本文对含有孪晶界的纳米孪晶铜的变形特征进行了原子尺度计算模拟。结果表明完美的无初始缺陷的孪晶界并不
曲绍兴*, 王贵民, 周昊飞, 黄志龙
(
浙江大学应用力学所; )
摘要:
实验发现带有初始缺陷的纳米孪晶界很容易成为位错源发射位错。本文对含有孪晶界的纳米孪晶铜的变形特征进行了原子尺度计算模拟。结果表明完美的无初始缺陷的孪晶界并不能成位错源。另一重要现象是在单向拉伸载荷作用下TB倾斜的模型中塑性变形机制主要靠TB沿法向方向的迁移运动实现。纳米压痕模拟过程中产生的的位错与TB相互作用后导致TB面折断,折断处形成的"台阶"使TB共格性能破坏,在接下来的变形中在共格关系破坏的TB面上有位错形核并向晶体内发射。
关键词:
孪晶界;位错源;孪晶界迁移
Qu Shaoxing*, Wang Guimin, Zhou Haofei, Huang Zhilong
(
Institute of Applied Mechanics, Zhejiang University; )
Abstract:
Nanoscale twin boundaries with initial defects are found to be easy dislocation sources in experiments. Here, deformation of nano-twinned single crystals is performed by using atomistic simulations. It is revealed that perfect TBs potentially are not dislocation sources. Another observation is that plastic deformation under uniaxial tensile loading can be dominated by TB migration in samples with inclined TB orientation. Twin planes with disconnections induced by dislocation-TB interactions are obtained during nanoindentation. Under further plastic deformation, it is observed that nucleation of dislocations occur at the disconnections where coherency of TBs has been destroyed.
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