Notch toughness of Cu-based bulk metallic glasses

We have measured the notch toughness for a range of Cu-based bulk metallic glasses (BMGs). Alloying additions that enhance the glass-forming ability (GFA) are found to degrade the toughness. Within this particular family of Cu-BMGs, toughness is more directly correlated with strength (and consequently with the shear modulus or glass transition temperature) than with the Poisson’s ratio. The Cu49Hf42Al9 BMG exhibits the best combination of GFA and toughness.