Dimiduk Dennis M, Woodward Chris, Lesar Richard, Uchic Michael D
Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/MLLM, Wright-Patterson AFB, OH 45433, USA.
Science. 2006 May 26;312(5777):1188-90. doi: 10.1126/science.1123889.
Under stress, crystals irreversibly deform through complex dislocation processes that intermittently change the microscopic material shape through isolated slip events. These underlying processes can be revealed in the statistics of the discrete changes. Through ultraprecise nanoscale measurements on nickel microcrystals, we directly determined the size of discrete slip events. The sizes ranged over nearly three orders of magnitude and exhibited a shock-and-aftershock, earthquake-like behavior over time. Analysis of the events reveals power-law scaling between the number of events and their magnitude, or scale-free flow. We show that dislocated crystals are a model system for studying scale-free behavior as observed in many macroscopic systems. In analogy to plate tectonics, smooth macroscopic-scale crystalline glide arises from the spatial and time averages of disruptive earthquake-like events at the nanometer scale.
在应力作用下，晶体通过复杂的位错过程发生不可逆变形，这些过程通过孤立的滑移事件间歇性地改变微观材料形状。这些潜在过程可以在离散变化的统计数据中揭示出来。通过对镍微晶进行超精确的纳米级测量，我们直接确定了离散滑移事件的大小。其大小范围跨越近三个数量级，并且随着时间呈现出类似地震的主震-余震行为。对这些事件的分析揭示了事件数量与其量级之间的幂律缩放关系，即无标度流。我们表明，位错晶体是研究许多宏观系统中观察到的无标度行为的模型系统。类似于板块构造，宏观尺度上的平滑晶体滑动源于纳米尺度上类似破坏性地震事件的空间和时间平均值。
