Lognormal Distribution of Local Strain: A Universal Law of Plastic Deformation in Material
Lognormal Distribution of Local Strain: A Universal Law of Plastic Deformation in Material
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局部应变的对数正态分布：材料塑性变形的普遍规律
DOI：
10.1103/physrevlett.124.155501
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发表时间：
2020
影响因子：
8.6
通讯作者：
Shen Yao
中科院分区：
文献类型：
--
作者：
Tang Ao;Liu Haiting;Liu Guisen;Zhong Yong;Wang Li;Lu Qi;Wang Jeff;Shen Yao
由于微观结构不均匀性的无限多样性，局部应变的空间分布变化可以是无限的。然而，本研究发现，无论相含量和变形机制如何，局部应变的统计分布普遍服从对数正态分布。此外，还证明了这一普遍规律是建立在统计窗口尺度上宏观变形均匀性的条件下的，即由窗口角位移计算的宏观应变与局部应变的平均值相等。对数正态分布规律的发现表明存在一个最小统计代表性窗口（MSRW）大小，它是每种材料的特征。探索MSRW尺寸对微观组织、变形机制和应变大小的依赖关系，有望为理解微观组织与力学性能之间的关系增加新的维度。
Given the infinite diversity of microstructural inhomogeneity, the variation in spatial distribution of local strain could be infinite. However, this study finds that the statistical distribution of local strain universally follows a lognormal distribution irrespective of phase content and deformation mechanism. Moreover, this universal law is proved conditional upon the macroscopic homogeneity of deformation on the statistical window scale, equivalent to the equality between the macrostrain calculated from the displacements at the window corners and the average of the local strain. The discovery of a lognormal distribution law suggests the existence of a minimum statistical representative window (MSRW) size that is characteristic for each material. Explorations on the dependence of MSRW size on the microstructure, deformation mechanism, and strain magnitude are expected to add new dimensions to understanding of the relationship between microstructure and mechanical properties.