Strain rate sensitivity and deformation behavior in a Ti-based bulk metallic glass composite

The Ti₄₅Zr₂₅Nb₆Sn₂Cu₅Be₁₇ bulk metallic glass composite was investigated by uniaxial quasi-static compression and tension tests under strain rates from 1 × 10^{− 4} s^{− 1} to 1 × 10^{− 2} s^{− 1} at the room temperature. The deformation behavior was characterized by analyzing the lateral and fracture surfaces. With the increase of strain rate, the yielding stress and plasticity decrease significantly, indicating negative strain rate sensitivity. At higher strain rates, the thermal softening effect is more prominent and the yielding stress is lower, while lower strain rates, the shear band toughness of the dendrites is higher than that of the glass matrix. Then the dislocations have sufficient time to be generated, multiplied and aggregated, thereby the shear banding can be retarded and hindered efficiently by dendrites. Furthermore, the primary shear bands are able to block more effectively the secondary ones, which results in more uniform distribution of plastic strain and thereby higher plasticity. The current work shows that the coordination of the shear band toughness of the dendrites and the glass matrix and the stable extension of the shear bands are of primary importance for obtaining excellent mechanical properties.