Kumar R Santhosh, Gupta Bhaskar Sen
Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India.
J Phys Condens Matter. 2021 Jun 17;33(31). doi: 10.1088/1361-648X/ac0474.
The generic response of a wide range of amorphous solids is the average increase of stress upon external loading until the yielding transition point, after which elasto-plastic steady state sets in. The stress-strain response comprises of a series of elastic branches interspersed with plastic drops. The ubiquitousness of these phenomena indicates universality, independent of material property, but the literature predominantly deals with specific materials. In pursuit of generality among different amorphous systems, we undertake a careful investigation in the mechanical response of metallic glasses using computer simulation. By comparing our results of multi-body metallic glass potentials to those obtained from pairwise Lennard-Jones glasses, we show that the mechanism of plastic instabilities is universal and independent of the details of the underlying potential. We also investigate the yielding transition in terms of the overlap parameter, which has been successfully used Lennard-Jones glasses. The yielding is unambiguously identified as a first-order phase transition. These observations conform the nature of plastic instabilities and mechanical yield as universal and independent of microscopic interactions.
各种非晶态固体的一般响应是，在外部加载时应力平均增加，直至屈服转变点，此后进入弹塑性稳态。应力-应变响应由一系列穿插着塑性下降的弹性分支组成。这些现象的普遍性表明其具有通用性，与材料特性无关，但文献主要关注特定材料。为了探寻不同非晶态系统之间的共性，我们利用计算机模拟对金属玻璃的力学响应进行了细致研究。通过将多体金属玻璃势的结果与从成对的 Lennard-Jones 玻璃获得的结果进行比较，我们表明塑性失稳的机制具有普遍性，且与潜在势的细节无关。我们还根据重叠参数研究了屈服转变，该参数已成功应用于 Lennard-Jones 玻璃。屈服被明确识别为一级相变。这些观察结果证实了塑性失稳和机械屈服的本质具有普遍性，且与微观相互作用无关。
