Ghosh Antina, Budrikis Zoe, Chikkadi Vijayakumar, Sellerio Alessandro L, Zapperi Stefano, Schall Peter
Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands.
Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany.
Phys Rev Lett. 2017 Apr 7;118(14):148001. doi: 10.1103/PhysRevLett.118.148001. Epub 2017 Apr 5.
When strained beyond the linear regime, soft colloidal glasses yield to steady-state plastic flow in a way that is similar to the deformation of conventional amorphous solids. Because of the much larger size of the colloidal particles with respect to the atoms comprising an amorphous solid, colloidal glasses allow us to obtain microscopic insight into the nature of the yielding transition, as we illustrate here combining experiments, atomistic simulations, and mesoscopic modeling. Our results unanimously show growing clusters of nonaffine deformation percolating at yielding. In agreement with percolation theory, the spanning cluster is fractal with a fractal dimension d_{f}≃2, and the correlation length diverges upon approaching the critical yield strain. These results indicate that percolation of highly nonaffine particles is the hallmark of the yielding transition in disordered glassy systems.
当应变超过线性范围时，软胶体玻璃会以类似于传统非晶态固体变形的方式进入稳态塑性流动。由于胶体颗粒的尺寸相对于构成非晶态固体的原子要大得多，胶体玻璃使我们能够深入了解屈服转变的本质，正如我们在此结合实验、原子模拟和介观模型所展示的那样。我们的结果一致表明，在屈服时，非仿射变形的簇不断增长并发生渗流。与渗流理论一致，跨越簇是分形的，分形维数(d_f)≃2，并且在接近临界屈服应变时相关长度发散。这些结果表明，高度非仿射颗粒的渗流是无序玻璃态系统中屈服转变的标志。
