A new continuum model for viscoplasticity in metallic glasses based on thermodynamics and its application to creep tests

•A chemo-mechanical continuum theory based on a thermodynamically consistent framework is developed in which the macroscopic plasticity is connected with the mass migration at the microscale.•A transition from stable to unstable creep around the threshold stress is captured by our model and the two distinct underlying mechanisms are identified.•The threshold stress is explained by the linear perturbation analysis.