Peierls stress of dislocations in molecular crystal cyclotrimethylene trinitramine.
Peierls stress of dislocations in molecular crystal cyclotrimethylene trinitramine.
复制标题
分子晶体环三亚甲基三硝胺中位错的 Peierls 应力。
DOI：
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发表时间：
2013
影响因子：
2.9
通讯作者：
P. Chung
中科院分区：
文献类型：
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作者：
N. Mathew;C. Picu;P. Chung
采用原子模拟和Peierls-Nabarro(PN)模型相结合的方法，研究了高能分子晶体环三亚甲基三硝胺(RDX)α相中位错的塑性。利用大气压下的非热原子模拟，对核心区结构和位错Peierls应力进行了详细的研究，以确定活动滑移系。在PN模型中使用原子模拟计算的广义层错能面来估计位错运动的临界剪应力。初步滑移面为(010)与实验观测一致，(010)[100]滑移系具有最低的Peierls应力。此外，原子模拟预测(021)[01[Overline]2]、(021)[100]、(011)[100]、(001)[100]和(001)[010]滑移系统具有足够小的Peierls应力值以允许塑性活动。然而，在所有情况下，这种材料中只有不到五个独立的滑移系统。给出了基于Peierls应力值的滑移系统的排序，并讨论了与纳米压痕和冲击诱导塑性变形的实验数据有关的含义。
Dislocation mediated plasticity in the α phase of the energetic molecular crystal cyclotrimethylene trinitramine (RDX) was investigated using a combination of atomistic simulations and the Peierls-Nabarro (PN) model. A detailed investigation of core structures and dislocation Peierls stress was conducted using athermal atomistic simulations at atmospheric pressure to determine the active slip systems. Generalized stacking fault energy surfaces calculated using atomistic simulations were used in the PN model to also estimate the critical shear stress for dislocation motion. The primary slip plane is found to be (010) in agreement with experimental observations, with the (010)[100] slip systems having the lowest Peierls stress. In addition, atomistic simulations predict the (021)[01[overline]2], (021)[100], (011)[100], (001)[100], and (001)[010] slip systems to have Peierls stress values small enough to allow plastic activity. However, there are less than five independent slip systems in this material in all situations. The ranking of slip systems based on the Peierls stress values is provided, and implications are discussed in relation to experimental data from nanoindentation and shock-induced plastic deformation.