Dynamic fracture of berylium-bearing bulk metallic glass systems: A cross-technique comparison

We report on a detailed comparison between two different experimental techniques used to measure the dynamic initiation fracture toughness K IC d of a bulk metallic glass system (Vitreloy-1) and its β-phase composite. Both the coherent gradient sensing interferometry (CGS) and one-point impact techniques reveal very similar trends in the K IC d – K ˙ I d relationship for Vitreloy-1. A drastic increase in initiation toughness with the stress intensity rate is observed. By contrast, the one-point impact method shows a relative rate-insensitivity for the K IC d of the β-phase composite. The results are rationalized through a detailed characterization of the failure mechanisms.