Investigation of Mode I Notch Toughness of Zr41.2Ti13.8Cu10Ni12.5Be22.5 Metallic Glass under Dynamic Loading Conditions

Based on dynamic three-point bending tests, the dynamic notch toughness (\( K_{\text{Q}}^{\text{d}} \)) of Zr41.2Ti13.8Cu10Ni12.5Be22.5 (Vit 1) bulk metallic glass (BMG) was found to be sensitive to stress intensity factor rate (\( \dot{K}_{\text{Q}}^{\text{d}} \)), which varied from 5.21 to 31.90 MPa m1/2. The number of shear bands (Ns) in the notch tip plastic zone was quantitatively analyzed. The phenomenon wherein Ns decreased with increasing loading rate was explained based on the theory of the shear transformation zone and the softening mechanism. Then, power law relationships were established among Ns, \( K_{\text{Q}}^{\text{d}} \) and \( \dot{K}_{\text{Q}}^{\text{d}} \). The results showed that shear bands can affect \( K_{\text{Q}}^{\text{d}} \) and \( \dot{K}_{\text{Q}}^{\text{d}} \) and act as a bridge connecting \( K_{\text{Q}}^{\text{d}} \) and \( \dot{K}_{\text{Q}}^{\text{d}} \). The sensitivity of \( K_{\text{Q}}^{\text{d}} \) to \( \dot{K}_{\text{Q}}^{\text{d}} \) in BMGs can be well explained by the variation of Ns with loading rate.