Dislocation ↔ twin transmutations during interaction between prismatic slip and {101¯1} twin in magnesium
Dislocation ↔ twin transmutations during interaction between prismatic slip and {101¯1} twin in magnesium
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DOI：
10.1016/j.actamat.2020.01.010
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发表时间：
2020-03
期刊：
影响因子：
9.4
通讯作者：
Peng Chen;Jamie Ombogo;Bin Li
中科院分区：
文献类型：
--
作者：
Peng Chen;Jamie Ombogo;Bin Li
在原子模拟中观察到镁 (Mg) 中的基体棱柱位错和 {10 1´ 1} 孪晶界 (TB) 之间非常不寻常且有趣的相互作用。当第一个棱柱位错撞击 TB 时，传入的位错转变为 {10 1´ 1} 孪晶内部的一薄层 {11 2´ 1} 孪晶。当同一滑移面上的连续棱柱位错碰撞到{10 1 ̣ 1} TB 的同一位置时，{11 2 ̣ 1} 孪晶不断向相反的{10 1 ̣ 1} TB 生长。最终，{11 2´ 1} 孪晶到达相反的 TB，然后转变回离开 {10 1´ 1} 孪晶的棱柱位错并滑入基体。因此，矩阵棱柱位错在双滑移相互作用期间暂时失去其位错特性，然后在相互作用完成后恢复其位错特性。这些相互作用的净效应是矩阵棱柱位错穿过{10 1¯ 1}孪晶传递。对 {10 1́ 1} 孪晶进行晶格对应分析，以了解相互作用的机制。结果表明，棱柱滑移面正是{11 2´ 1}孪晶的对应面。这种对应关系与基于经典孪晶理论的晶体学计算一致。
Very unusual and interesting interaction between matrix prismatic dislocations and {10 1¯ 1} twin boundaries (TBs) in Magnesium (Mg) was observed in atomistic simulations. When the first prismatic dislocation impinged on the TB, the incoming dislocation was transmuted into a thin layer of {11 2¯ 1} twin inside the {10 1¯ 1} twin. When successive prismatic dislocations on the same slip plane impinged on the same location at the {10 1¯ 1} TB, the {11 2¯ 1} twin kept growing toward the opposite {10 1¯ 1} TB. Eventually, the {11 2¯ 1} twin reached the opposite TB and was then transmuted back to prismatic dislocations that exited the {10 1¯ 1} twin and glided into the matrix. Hence, the matrix prismatic dislocations temporarily lose their dislocation identity during twin-slip interaction and then resume their dislocation identity after the interaction is complete. The net effect of these interactions is that the matrix prismatic dislocations transmit across the {10 1¯ 1} twin. Lattice correspondence analysis for {10 1¯ 1} twinning was performed to understand the mechanism of the interactions. The results show that, the prismatic slip plane is exactly the corresponding plane of {11 2¯ 1} twinning. Such a correspondence is consistent with the crystallographic calculations based on classical twinning theory.