J. Mater. Sci. Technol. ›› 2020, Vol. 38: 73-79.DOI: 10.1016/j.jmst.2019.08.022

• Research Article • Previous Articles     Next Articles

Rejuvenated metallic glass strips produced via twin-roll casting

Long Zhanga*(), Yi Wuab, Shidong Fengcd, Wen Lib, Hongwei Zhanga, Huameng Fua, Hong Lia, Zhengwang Zhua, Haifeng Zhanga*()   

  1. aShenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    bShenyang Ligong University, Shenyang 110159, China
    cAdvanced Manufacturing Technology Research Centre, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong, China
    dState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
  • Received:2019-07-07 Revised:2019-07-31 Accepted:2019-08-12 Published:2020-02-01 Online:2020-02-10
  • Contact: Zhang Long,Zhang Haifeng

Abstract:

The energy state and atomic level structure of metallic glasses (MGs) are very sensitive to their cooling rates, and a lower cooling rate generally causes a lower energy and more relaxed state of MGs. In this work, the Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit. 1) ribbons with a thickness of 40 μm and 110 μm and the strips with a thickness of 320 μm and 490 μm were produced by single-roll melt spinning and twin-roll casting, respectively. The increase in thickness of either ribbons or strips results in a lower energy state with a smaller relaxation enthalpy, a lower content of free volume, and a higher hardness. Although the cooling rate of the twin-roll produced 320 μm-thick strip is almost one magnitude lower than that of the single-roll produced 110 μm-thick ribbon, the former, however, possesses a rejuvenated energy state as compared to the latter. Molecular dynamics simulations reveal that the squeezing force during twin-roll casting affects the evolution of connection types of clusters, and the 2-atom and 4-atom connections are prone to be retained, which results in a higher energy state of MGs. Such a rejuvenation process during twin-roll casting can overwhelm the relaxation process caused by the lower cooling rate. Therefore, twin-roll casting is not only a method being capable for producing strips with a large thickness, but also prone to obtain a high energy state of the MG strip.

Key words: Metallic glass, Metallic glass strip, Twin-roll casting, Rejuvenation, Cluster connection