Free volume measurement of severely deformed Zr62Cu22Al10Fe5Dy1 bulk metallic glass

The Zr62Cu22Al10Fe5Dy1 bulk metallic glass (BMG) was subjected to high pressure torsion (HPT) at room temperature and at 150 °C. XRD shows a shift of first amorphous halo towards a low angles, which corresponds to an increase in the first coordination sphere radius and an increase in free volume content approximately by 0.44 % and 0.74 % after HPT processing at temperatures of 20 and 150 °C, respectively. Direct density measurements revealed that HPT at 20 °C and 150 °C leads to a decrease in the density values by 2.1% and 1 %, respectively, in comparison with the initial state. Value of density decrease for state HPT 150 °C estimated by direct density measurements is close to value of free volume increase estimated by shift of first amorphous halo.