Factors Affecting Temperature Rise in Shear Bands in a Simulated CuZr Metallic Glass

The temperature rise in shear bands is of significant importance for the mechanical behaviour of metallic glasses since it changes their atomic structure and viscosity. However, experimental measurement of any temperature rise of a shear band is difficult, due to their temporal and spatial localization within the bulk. Molecular dynamics simulations were carried out on a CuZr metallic glass under tensile loading. It is shown that the observed temperature rise in a shear band, ranging from ~25 K up to the melting point of the alloy, correlates linearly with the maximum sliding velocity of the shear band, which is a function of both sample size and loading rate. In response to the high energy flux into the shear band, shear band bifurcation occurs and hinders further temperature rise well above the melting point. This negative feedback mechanism imposes an upper limit of temperature rise in a shear band before the theoretical limit of shear velocity is reached.