High strain rate in situ micropillar compression of a Zr-based metallic glass
Rajaprakash Ramachandramoorthy, Fan Yang, Daniele Casari, Moritz Stolpe, Manish Jain, Jakob Schwiedrzik, Johann Michler, Jamie J. Kruzic, James P. Best
Abstract
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