Cu<SUB>45</SUB>Zr<SUB>45</SUB>Al<SUB>5</SUB>Ag<SUB>5</SUB> Bulk Glassy Alloy with Enhanced Compressive Strength and Plasticity at Cryogenic Temperature

Abstract

Compressive tests were made for the as-cast Cu 45 Zr 45 Al 5 Ag 5 bulk glassy alloy rods with a diameter of 3 mm at 298 and 77 K, at an initial strain rate of 5 × 10 -4 s -1 . It was found that at 77 K, the compressive yield strength, maximum strength and plastic strain to fracture of the glassy alloy rod are higher than those at 298 K. The maximum strength measured at 77 K is about 13% larger than that measured at 298 K. In particular, its plasticity at 77 K is significantly enhanced. SEM observations reveal that more shear bands appear near the fracture plane at 77 K. The higher strength and ductility at a cryogenic temperature (77 K) are probably due to the lower mobility of the squeezed free volume.