Maass R, Wraith M, Uhl J T, Greer J R, Dahmen K A
California Institute of Technology, Division of Engineering and Applied Sciences, 1200 East California Boulevard, Pasadena, California 91125, USA.
University of Illinois at Urbana-Champaign, Department of Physics, 1110 West Green Street, Urbana, Illinois 61801, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Apr;91(4):042403. doi: 10.1103/PhysRevE.91.042403. Epub 2015 Apr 14.
Slowly compressed microcrystals deform via intermittent slip events, observed as displacement jumps or stress drops. Experiments often use one of two loading modes: an increasing applied stress (stress driven, soft), or a constant strain rate (strain driven, hard). In this work we experimentally test the influence of the deformation loading conditions on the scaling behavior of slip events. It is found that these common deformation modes strongly affect time series properties, but not the scaling behavior of the slip statistics when analyzed with a mean-field model. With increasing plastic strain, the slip events are found to be smaller and more frequent when strain driven, and the slip-size distributions obtained for both drives collapse onto the same scaling function with the same exponents. The experimental results agree with the predictions of the used mean-field model, linking the slip behavior under different loading modes.
缓慢压缩的微晶通过间歇性滑移事件发生变形，表现为位移跳跃或应力下降。实验通常采用两种加载模式之一：增加施加应力（应力驱动，软加载）或恒定应变率（应变驱动，硬加载）。在这项工作中，我们通过实验测试了变形加载条件对滑移事件标度行为的影响。结果发现，这些常见的变形模式强烈影响时间序列特性，但在用平均场模型分析时，并不影响滑移统计的标度行为。随着塑性应变的增加，发现应变驱动时滑移事件更小且更频繁，并且两种驱动方式下获得的滑移尺寸分布都塌缩到具有相同指数的相同标度函数上。实验结果与所用平均场模型的预测一致，该模型将不同加载模式下的滑移行为联系起来。
