Effect of strain on the stacking fault energy of copper: A first-principles study
Effect of strain on the stacking fault energy of copper: A first-principles study
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DOI：
10.1103/physrevb.88.064104
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发表时间：
2013-08-26
影响因子：
3.7
通讯作者：
Srolovitz, D. J.
中科院分区：
文献类型：
--
作者：
Branicio, P. S.;Zhang, J. Y.;Srolovitz, D. J.
使用密度泛函理论 (GGA-PBE) 研究铜在体积应变、纵向应变和剪切应变下的本征堆垛层错能 (SFE)。使用垂直于 (111) 本征堆垛层错面排列的铜板模型进行计算。计算得出的无应变铜的 SFE 为 gamma = 41 mJ/m(2)。结果表明，伽玛对应变有很强的依赖性，并且不同类型的应变具有不同的行为：（a）垂直于堆垛层错方向的体积和纵向，（b）平行于堆垛层错的纵向，以及（c）平行于堆垛层错的剪切。在第一种情况 (a) 中，SFE 随应变单调减小，对于体积和纵向，斜率 d gamma/d epsilon 垂直条(epsilon=0) = -0.44 J/m(2) 和 -0.87 J/m(2)，并且 d(2)gamma/d epsilon(2) > 0。相反，对于平行于 堆垛层错 (b) 时，SFE 依赖性表现出 d(2)gamma/d epsilon(2) < 0，epsilon 处的最大值近似为 -0.015。对于平行于堆垛层错 (c) 的剪切情况，SFE 在小应变和中等大应变下几乎恒定，但在非常大的应变下迅速下降（对于 epsilon = +/- 0.1 时的 {111} 剪切，SFE 下降 1/3）。对于大 < 11 (2) 超过杆 >{111} 剪切应变，SFE 可以在大应变下增加或减少，具体取决于应变的符号。在边界平面（以及某些剪切方向）的体积或纵向（垂直于堆垛层错）张力和纵向应变中，SFE 可能变为负值，这意味着面心立方晶体结构的稳定性受到限制。 SFE 对应变的强烈依赖性表明对金属在高压、剧烈塑性变形和冲击载荷条件下的机械性能、微观结构演变和动态塑性具有深远的影响。
The intrinsic stacking fault energy (SFE) of copper under volumetric, longitudinal, and shear strains is investigated using density functional theory (GGA-PBE). Calculations are performed using a copper slab model aligned perpendicular to the (111) intrinsic stacking fault plane. The calculated SFE for unstrained copper is gamma = 41 mJ/m(2). Results show a strong dependence of gamma on strain and distinct behavior for different types of strain: (a) volumetric and longitudinal in the direction perpendicular to the stacking fault, (b) longitudinal parallel to the stacking fault, and (c) shear parallel to the stacking fault. In the first case (a), the SFE decreases monotonically with strain with a slope d gamma/d epsilon vertical bar(epsilon=0) = -0.44 J/m(2) and -0.87 J/m(2) for volumetric and longitudinal, respectively, and with d(2)gamma/d epsilon(2) > 0. In contrast, for longitudinal strain parallel to the stacking fault (b), the SFE dependence exhibits d(2)gamma/d epsilon(2) < 0 with a maximum at epsilon approximate to -0.015. For the case of shear parallel to the stacking fault (c), the SFE is nearly constant at small and moderately large strain, but drops rapidly at very large strain (by a factor of 1/3 for {111} shear at epsilon = +/- 0.1). For large < 11 (2) over bar >{111} shear strains, the SFE can either increase or decrease at large strain depending on the sign of the strain. In volumetric or longitudinal (perpendicular to the stacking fault) tension and longitudinal strain in the boundary plane (and for some shear directions), the SFE can become negative, implying a limit on the stability of the fcc crystal structure. The strong dependence of the SFE on strain suggests deep implications for the mechanical properties, microstructural evolution, and dynamic plasticity of metals at high pressure, during severe plastic deformation, and in shock-loading conditions.