Shear stress induced reduction of glass transition temperature in a bulk metallic glass

In contrast to previous observations of a slight increase in glass transition temperature (T-g) under hydrostatic pressure, we report, for the first time, a drastic reduction of T-g (40 K/500 MPa) induced by shear stress in a Zr46.75Ti8.25Cu7.5Ni10.0Be27.5 bulk metallic glass, which gives rise to the experimental observation of the drastic decrease in flow temperature while a compressive stress was applied. The significant T-g reduction is attributed to a large activation volume of relaxation U V-t under shear stress (126 A(3)), and can be quantitatively interpreted in terms of the free volume model. C 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.