Relationship between the entropy of mixing, excess entropy and the shear viscosity of metallic glasses near the glass transition

We measured the shear viscosity of 14 metallic glasses (MGs) differing with their mixing entropy ΔS_mix. It is found that the viscosity at the glass transition temperature T_g significantly increases with ΔS_mix. Using calorimetric data, we calculated the excess entropy ΔS of all MGs with respect to their maternal crystalline states as a function of temperature. It is shown that the excess entropy ΔS both at room temperature and at T_g decreases with ΔS_mix. It is concluded that glasses with ‘high mixing entropy’ ΔS_mix correspond to MGs with low excess entropy ΔS. The origin of the increased shear viscosity at T_g of glasses with high ΔS_mix is determined by their reduced excess entropy ΔS.