Pattern formation in a minimal model of continuum dislocation plasticity
Pattern formation in a minimal model of continuum dislocation plasticity
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DOI：
10.1088/0965-0393/23/6/065005
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发表时间：
2015-01
影响因子：
1.8
通讯作者：
S. Sandfeld;M. Zaiser
中科院分区：
文献类型：
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作者：
S. Sandfeld;M. Zaiser
异质位错花样的自发出现是晶态固体塑性变形和应变硬化的显著特征。尽管在材料科学和缺陷社区的物理学方面进行了长期的努力，但对于导致位错图案形成的物理机制还没有达成普遍的共识。为了建立基本的机制，我们根据弯曲位错通量的连续统理论，建立了一个极其简化的最小模型来研究花样的形成。我们证明，应变硬化体现为泰勒型位错密度对流动应力的依赖，再加上在外应力作用下控制位错运动的运动学方程的结构，已经足以形成符合相似原理的位错图案。
The spontaneous emergence of heterogeneous dislocation patterns is a conspicuous feature of plastic deformation and strain hardening of crystalline solids. Despite long-standing efforts in the materials science and physics of defect communities, there is no general consensus regarding the physical mechanism which leads to the formation of dislocation patterns. In order to establish the fundamental mechanism, we formulate an extremely simplified, minimal model to investigate the formation of patterns based on the continuum theory of fluxes of curved dislocations. We demonstrate that strain hardening as embodied in a Taylor-type dislocation density dependence of the flow stress, in conjunction with the structure of the kinematic equations that govern dislocation motion under the action of external stresses, is already sufficient for the formation of dislocation patterns that are consistent with the principle of similitude.