High strain rate in situ micropillar compression of a Zr-based metallic glass

Rajaprakash Ramachandramoorthy,Daniele Casari,Jakob Schwiedrzik,Fan Yang,James P Best,Jamie J Kruzic,Manish Jain,Johann Michler,Moritz Stolpe

doi:10.1557/s43578-021-00187-5

Abstract

High strain rate micromechanical testing can assist researchers in elucidating complex deformation mechanisms in advanced material systems. In this work, the interactions of atomic-scale chemistry and strain rate in affecting the deformation response of a Zr-based metallic glass was studied by varying the concentration of oxygen dissolved into the local structure. Compression of micropillars over six decades of strain rate uncovered a remarkable reversal of the strain rate sensitivity from negative to positive above ~ 5 s−1 due to a delocalisation of shear transformation events within the pre-yield linear regime for both samples, while a higher oxygen content was found to generally decrease the strain rate sensitivity effect. It was also identified that the shear band propagation speed increases with the actuation speed, leading to a transition in the deformation behaviour from serrated to apparent non-serrated plastic flow at ~ 5 s−1.Graphic abstract

Highlights

Bulk metallic glasses (BMGs) possess an amorphous structure that exhibits superior strength compared to their crystalline counterparts
Differential scanning calorimetry (DSC) results presented in Fig. 1a,b demonstrate a typical glassy thermal response, where similarities in the curve shapes and transitions can be observed for both samples
Differences were observed in the crystallisation peak, where a much wider peak of 3.2 °C full width at half maximum (FWHM) was observed for the (AMZ4)L sample compared to 1.1 °C FWHM for the (AMZ4)H sample

Summary

Introduction

Bulk metallic glasses (BMGs) possess an amorphous structure that exhibits superior strength compared to their crystalline counterparts. The interactions of atomic-scale chemistry and strain rate in affecting the deformation response of a Zr-based metallic glass was studied by varying the concentration of oxygen dissolved into the local structure.

Results

Conclusion