Regular Article

Comparison of structural heterogeneity in Zr- and Pd-based metallic glasses

¹ Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
² School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China

^* e-mail: hao.wang.e4@tohoku.ac.jp

Received: 30 January 2023
Received in final form: 8 February 2023
Accepted: 20 February 2023
Published online: 29 March 2023

Abstract

Metallic glasses (MGs) are known to exhibit a nanoscale heterogeneous structure that consists of a weakly bonded region (WBR) and a strongly bonded region (SBR), but its characterization is not yet fully understood. This study investigates the structural heterogeneity of Zr- and Pd-based MGs using a dynamic viscoelastic model. Volume fraction (V) and elastic modulus (E_c) are independently derived from the model to characterize each region. In addition, the structural heterogeneity is evaluated using χ = VE_c,WBR/VE_c,total. As a result, the strong Zr-based MG is estimated to own approximately 28% of V_WBR, approximately 87% of E_c,WBR/E_c,SBR, and χ ∼ 0.241. On the other hand, the fragile Pd-based MG is estimated to own approximately 26% of V_WBR, approximately 70% of E_c,WBR/E_c,SBR, and χ ∼ 0.208. Furthermore, a comparison of χ, fragility, and Poisson's ratio shows that as χ increases, fragility decreases and Poisson's ratio increases. Notably, the diversification of constituent elements is inversely related to χ, fragility, and Poisson's ratio in the Zr- and Pd-based MGs. Thus, the existing understanding of the structural heterogeneity inherent in MGs is updated using the constructed dynamic viscoelastic model in this study.