Rheology and nano-crystallization of a Zr 41.25 Ti 13.75 Ni 10 Cu 12.5 Be 22.5 bulk metallic glass

Abstract

Creep of Zr-based bulk metallic glass (BMG) was carried out under hydrostatic pressure of 270 MPa superimposed on uniaxial compressive loads of 30-300 MPa. The temperature of testing was maintained at 633 K, which is close to the glass transition temperature of the BMG. The samples had heat treatment at 676 K for different lengths of time applied prior to testing, which resulted in microstructural changes. Apparent viscosity during flow was derived from the creep measurements. The effect of crystalline volume fraction, temperature, and strain rate are considered. Finally, we have constructed a TTT diagram for this BMG spanning almost three decades of time and 650-690 K temperature range, showing transformation from glassy to crystalline solid as a function of volume fraction. Show more