Rejuvenation in Hot-Drawn Micrometer Metallic Glassy Wires
Jie Dong1,2, Yi-Hui Feng3, Yong Huan3, Jun Yi4, Wei-Hua Wang1,2,5, Hai-Yang Bai1,2,5**, Bao-An Sun1,5**
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190 2College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049 3State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 4Institute of Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444 5Songshan Lake Materials Laboratory, Dongguan 523808
Abstract：We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires (MG wires) with the size reduction. Compared to metallic glasses (MGs) in bulk form, the modulus and hardness for the micro-scale MG wires, tested by nanoindentation methods, are much lower and decrease with the decreasing size, with a maximum decrease of $\sim $26% in modulus and $\sim $17% in hardness. This pronounced rejuvenation is evidenced by the larger sub-$T_{\rm g}$ relaxation enthalpy of the MG wires. The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear flow into a constrained small-volume region. Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature, flow stress and size.
2020, Vol. 37 
