Tuning the mechanical performance of a Ti-based bulk metallic glass by pre-deformation

Prior plastic deformation processing was utilized to tune the mechanical performance of Ti₄₀Zr₂₅Ni₃Cu ₁₂Be₂₀ bulk metallic glass. After shear pre-deformation, the variations in the mechanical properties and the free volume content were examined by recourse to differential scanning calorimetry (DSC), X-ray diffraction (XRD), Vickers hardness measurements and uniaxial compression tests. The plastic strain prior to failure of the pre-deformed samples first increases and then decreases with increasing prior plastic strain. The hardness values of the pre-deformed samples exhibit an opposite trend. The variations in the mechanical performance for the pre-deformed samples were ascribed to the variation in free volume content associated with the competition between the annihilation process by diffusion atomic jumping and the stress-driven free volume creation.