COMP Centre of Excellence, Department of Applied Physics, Aalto University, P.O.Box 11100, FI-00076 Aalto, Espoo, Finland.
Center for Complexity and Biosystems, Department of Physics, University of Milano, via Celoria 16, 20133 Milano, Italy.
Sci Rep. 2017 Mar 30;7:45550. doi: 10.1038/srep45550.
Cyclically loaded disordered particle systems, such as granular packings and amorphous media, display a non-equilibrium phase transition towards irreversibility. Here, we investigate numerically the cyclic deformation of a colloidal polycrystal with impurities and reveal a transition to irreversible behavior driven by the displacement of dislocations. At the phase transition we observe enhanced particle diffusion, system size effects and broadly distributed strain bursts. In addition to provide an analogy between the deformation of amorphous and polycrystalline materials, our results allow to reinterpret Zener pinning of grain boundaries as a way to prevent the onset of irreversible crystal ordering.
循环加载的无序粒子系统，如颗粒堆积物和非晶态介质，会朝着不可逆的方向发生非平衡相变。在这里，我们通过数值模拟研究了含有杂质的胶体多晶体的循环变形，并揭示了由位错位移驱动的不可逆行为的转变。在相变过程中，我们观察到了增强的粒子扩散、系统尺寸效应和广泛分布的应变爆发。除了为非晶态和多晶态材料的变形提供类比之外，我们的结果还允许将晶界的 Zener 钉扎重新解释为防止不可逆晶体有序化发生的一种方法。
