Yan Zhijie, Song Kaikai, Hu Yong, Dai Fuping, Chu Zhibing, Eckert Jürgen
School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan, 030024, P. R. China.
IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden, Germany.
Sci Rep. 2016 Jan 13;6:19358. doi: 10.1038/srep19358.
Stress-induced viscous flow is the characteristic of atomic movements during plastic deformation of metallic glasses in the absence of substantial temperature increase, which suggests that stress state plays an important role in mechanically induced crystallization in a metallic glass. However, it is poorly understood. Here, we report on the stress-induced localized crystallization in individual shear bands of Zr60Al15Ni25 metallic glass subjected to cold rolling. We find that crystallization in individual shear bands preferentially occurs in the regions neighboring the amorphous matrix, where the materials are subjected to compressive stresses demonstrated by our finite element simulations. Our results provide direct evidence that the mechanically induced crystallization kinetics is closely related with the stress state. The crystallization kinetics under compressive and tensile stresses are interpreted within the frameworks of potential energy landscape and classical nucleation theory, which reduces the role of stress state in mechanically induced crystallization in a metallic glass.
应力诱导粘性流动是金属玻璃在无显著温度升高情况下塑性变形过程中原子运动的特征，这表明应力状态在金属玻璃的机械诱导结晶中起重要作用。然而，对此了解甚少。在此，我们报道了Zr60Al15Ni25金属玻璃在冷轧过程中单个剪切带内的应力诱导局部结晶。我们发现单个剪切带内的结晶优先发生在与非晶基体相邻的区域，有限元模拟表明这些区域承受压缩应力。我们的结果提供了直接证据，证明机械诱导结晶动力学与应力状态密切相关。在势能景观和经典成核理论的框架内解释了压缩应力和拉伸应力下的结晶动力学，这降低了应力状态在金属玻璃机械诱导结晶中的作用。
