Stable shear of Cu₄₆Zr₄₇Al₇ bulk metallic glass alloy by controlling temperature rise

Cu₄₆Zr₄₇Al₇ bulk metallic glass (BMG) alloys with different microstructure were fabricated by adjusting the casting size. For the monolithic BMG with different diameters, the measured plasticity decreased with the increase of sample size and was mainly due to the sliding of two undeveloped parts along main shear band. Excellent compression plastic strain (∼13.2%) was obtained for the marginal BMG containing in situ nanocrystals with sample size up to 3.5mm in diameter where multiple shear bands formed. It is suggested that failure of BMG samples will occur when the temperature rise in shear layer reaches a critical value. The temperature rise is closely related to the sample size and stress drop, moreover, it can be controlled through adjusting final stress drop (via sample size) and increment rate of stress drop (via microstructure), resulting in enhanced plasticity.