Assessing the shear band velocity in metallic glasses using a coupled thermo-mechanical model

Shear band (SB) velocity is a key parameter in assessing the dynamic behavior and also deformation mechanisms of metallic glasses. Using a coupled thermo-mechanical model, we calculated the speed of SB propagation in Vitreloy 1 (Zr41.25Ti13.75Ni10Cu12.5Be22.5) under compression at a strain rate of 10 s(-1). The propagation of the SB exhibits a non-uniform speed: a rather slow stage followed by a rapid propagation when the SB is close to the sample surface or at failure. The average speed is estimated to be about 100 m/s, while the maximum speed could reach 1400 m/s. The impact of the varying SB velocity on measurement relying on surface detection such as thermographic images, strain gauge, and surface offsets is discussed.