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 Delta S-mix. It is found that the viscosity at the glass transition temperature T-g significantly increases with Delta S-mix. Using calorimetric data, we calculated the excess entropy Delta S of all MGs with respect to their maternal crystalline states as a function of temperature. It is shown that the excess entropy Delta S both at room temperature and at T-g decreases with Delta S-mix. It is concluded that glasses with 'high mixing entropy' Delta S-mix correspond to MGs with low excess entropy Delta S. The origin of the increased shear viscosity at T-g of glasses with high Delta S-mix is determined by their reduced excess entropy Delta S.