Zhao Yue, Dezerald Lucile, Pozuelo Marta, Zhou Xinran, Marian Jaime
Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.
Department of Materials Science and Engineering, Institut Jean Lamour, Université de Lorraine, F-54011, Nancy, France.
Nat Commun. 2020 Mar 6;11(1):1227. doi: 10.1038/s41467-020-15085-3.
The Portevin-Le Chatelier (PLC) effect is a phenomenon by which plastic slip in metallic materials becomes unstable, resulting in jerky flow and the onset of inhomogeneous deformation. The PLC effect is thought to be fundamentally caused by the dynamic interplay between dislocations and solute atoms. However, this interplay is almost always inaccessible experimentally due to the extremely fine length and time scales over which it occurs. In this paper, simulations of jerky flow in W-O interstitial solid solutions reveal three dynamic regimes emerging from the simulated strain rate-temperature space: one resembling standard solid solution strengthening, another one mimicking solute cloud formation, and a third one where dislocation/solute coevolution leads to jerky flow as a precursor of dynamic strain aging. The simulations are carried out in a stochastic framework that naturally captures rare events in a rigorous manner, providing atomistic resolution over diffusive time scales using no adjustable parameters.
波特万-勒夏特列（PLC）效应是一种使金属材料中的塑性滑移变得不稳定的现象，会导致急跳流动和不均匀变形的开始。人们认为PLC效应从根本上是由位错与溶质原子之间的动态相互作用引起的。然而，由于这种相互作用发生的长度和时间尺度极其微小，几乎总是无法通过实验来探究。在本文中，对W-O间隙固溶体中的急跳流动进行的模拟揭示了在模拟的应变速率-温度空间中出现的三种动态状态：一种类似于标准固溶强化，另一种模拟溶质云的形成，第三种是位错/溶质共同演化导致急跳流动，作为动态应变时效的前兆。模拟是在一个随机框架中进行的，该框架以严格的方式自然地捕捉罕见事件，无需可调参数即可在扩散时间尺度上提供原子分辨率。
