Indentation plastic work and large compression plasticity in in situ nanocrystallized Zr62Cu18Ni10Al10 bulk metallic glass

Large plasticity is observed during uniaxial macroscopic compression of Zr62Cu18Ni10Al10 bulk metallic glass. Nanoindentation experiments, performed on the as-cast and compressed specimens, confirm the enhanced plasticity after compression. Indeed, the ratio between the plastic and the total indentation energies, Upl/Utot, is larger in the compressed sample than in the as-cast alloy. Furthermore, in both samples, Upl/Utot tends to progressively increase with the maximum indentation applied load, thus confirming the tendency towards enhanced plasticity as deformation proceeds. Transmission electron microscopy reveals that deformation (induced either by macroscopic compression tests or nanoindentation) causes partial nanocrystallization of the glass. This effect is likely to play a crucial role in the observed plasticity and also results in mechanical hardening.

Research highlights▶ In this study, the origin of large plasticity in Zr-based metallic glass is investigated. ▶ The values of indentation plastic energy are used to monitor the evolution of plasticity in the as-cast and deformed Zr-based metallic glass. ▶ Deformation-induced nanocrystallization is found to be responsible for the large plasticity observed.