Formation of grain boundaries in ductile single crystals at finite plastic deformations
Formation of grain boundaries in ductile single crystals at finite plastic deformations
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DOI：
10.1016/j.ijplas.2015.02.010
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发表时间：
2015-06
影响因子：
9.8
通讯作者：
M. Koster;K. Le;B. D. Nguyen
中科院分区：
文献类型：
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作者：
M. Koster;K. Le;B. D. Nguyen
在非线性连续位错理论（CDT）中提出了延性单晶晶界形成的理论，其中晶界被解释为在放置时弱不连续而在塑性滑移时强不连续的表面。从变分原理出发，导出了允许这种不连续曲面的能量极小值的控制方程集和跳跃条件。通过对平面应变、单轴剪切和单轴压缩下塑性单晶变形的两个实例，构造具有分段恒定塑性和弹性变形的能量最小化序列，表明具有晶界的片状结构的形成在能量上是可取的。通过最小化晶界能量加上边界层能量来估计片层的数量。
The theory of formation of grain boundaries in ductile single crystals is proposed within the nonlinear continuum dislocation theory (CDT), where grain boundaries are interpreted as surfaces of weak discontinuity in placement but strong discontinuity in plastic slip. The set of governing equations and jump conditions are derived for the energy minimizers admitting such surfaces of discontinuity from the variational principle. By constructing energy minimizing sequences having piecewise constant plastic and elastic deformation in two examples of ductile single crystals deforming in plane strain simple shear or uniaxial compression, it is shown that the formation of lamellae structure with grain boundaries is energetically preferable. The number of lamellae is estimated by minimizing the energy of grain boundaries plus the energy of boundary layers.