The heat release in the quasi-static tension of the magnesium alloy AZ31B is analyzed as a function of the strain rate and it is shown that with increasing deformation rate the fraction of energy going to structural transformations in materials decreases. The main factor affecting the thermodynamics of deformation is the inertia of the structural transformations processes. The magnesium alloy was studied under dynamic loading under conditions of electrical explosion of conductors. The spall strength of the alloy AZ31B is determined.