Viscosity-related properties of Mg65Cu25Y10 bulk metallic glass determined by uniaxial tension in the supercooled liquid region

Abstract The tensile flow behaviour of Mg 65 Cu 25 Y 10 bulk metallic glass (BMG) was investigated in the supercooled liquid (SCL) region over a range of strain rates (10 −3 to 10 −1 /s) and temperatures (150–175 °C). During testing, there was an increase in flow stress to a maximum value followed by either fracture or a decrease in stress to a very low steady-state value. Elongations of over 1000% were possible during testing at high temperatures and low strain rates. The temperature dependence of equilibrium viscosity of the BMG in the SCL region was adequately described by the Vogel–Fulcher–Tammann (VFT) equation. The fragility parameter was computed as m  = 33 which indicates that the alloy exhibits moderate-to-strong liquid behaviour and, hence, moderate-to-good resistance to crystallization. The present tensile test results were entirely consistent with previous researches on the same alloy deformed by different modes in the SCL region.