Shao Zhen, Singer Jonathan P, Liu Yanhui, Liu Ze, Li Huiping, Gopinadhan Manesh, O'Hern Corey S, Schroers Jan, Osuji Chinedum O
Department of Chemical and Environmental Engineering, Yale University, New Haven Connecticut 06511, USA.
Center for Research on Interface Structures and Phenomena, Yale University, New Haven Connecticut 06511, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Feb;91(2):020301. doi: 10.1103/PhysRevE.91.020301. Epub 2015 Feb 18.
A bulk metallic glass forming alloy is subjected to shear flow in its supercooled state by compression of a short rod to produce a flat disk. The resulting material exhibits enhanced crystallization kinetics during isothermal annealing as reflected in the decrease of the crystallization time relative to the nondeformed case. The transition from quiescent to shear-accelerated crystallization is linked to strain accumulated during shear flow above a critical shear rate γ̇(c)≈0.3 s(-1) which corresponds to Péclet number, Pe∼O(1). The observation of shear-accelerated crystallization in an atomic system at modest shear rates is uncommon. It is made possible here by the substantial viscosity of the supercooled liquid which increases strongly with temperature in the approach to the glass transition. We may therefore anticipate the encounter of nontrivial shear-related effects during thermoplastic deformation of similar systems.
一种大块金属玻璃形成合金在其过冷状态下通过对短棒进行压缩使其受到剪切流作用，从而制成扁平圆盘。所得材料在等温退火过程中表现出增强的结晶动力学，这体现在相对于未变形情况结晶时间的减少上。从静态结晶到剪切加速结晶的转变与在高于临界剪切速率γ̇(c)≈0.3 s⁻¹ 的剪切流过程中积累的应变有关，该临界剪切速率对应于佩克莱数，Pe∼O(1)。在适度剪切速率下在原子体系中观察到剪切加速结晶并不常见。在此处之所以能够实现，是因为过冷液体具有很大的粘度，在接近玻璃转变温度时粘度随温度强烈增加。因此，我们可以预期在类似体系的热塑性变形过程中会遇到与剪切相关的重要效应。
