Improvement of intrinsic plasticity and strength of Zr_(55)Cu_(30)Ni_5A_(10) metallic glass by tuning the glass transition temperature

摘要

We report the tuning of the glass transition temperature (T-g) in Zr55Cu30Ni5Al10 metallic glass by rolling at room temperature. The precise thermo-analytical measurements using step-scan modulated temperature differential scanning calorimeter (MTDSC) revealed a decrease of T-g by 16.9 K in ribbons and 7.1 K in bulk glassy plates upon 40% and 70% thickness reduction, respectively. The cold rolled plates exhibit higher yield strength up to sigma(y) = 1.66 GPa and larger plastic strain (epsilon(p) = 8.0%) before failure than that of as-cast plates (sigma(y) = 1.45 GPa). Transmission electron microscopy and DSC studies suggest that a relaxed structure has evolved due to the deformation induced structural change upon rolling, which reduces the activation energy of the shear transformation zone and improves the inherent plasticity of the glassy phase.