Hydrogen effect on the plastic deformation of a Zr-based bulk metallic glass during instrumented indentation test

Abstract

Although metallic glasses have been often considered for hydrogen storage materials, the influence of hydrogen on the plastic deformation of the bulk metallic glasses (BMGs) has attracted relatively less attention in the research field. As an effort to shed additional light on the topics, here we performed a series of instrumented macro- and nano-indentation experiments on the Zr-based BMG samples which were hydrogen-charged under a current density of a mA/cm2 for different time up to 200 h. First, we examined the inhomogeneous plastic deformation of a Zr-based BMG by performing macroscopic instrumented indentation (with a spherical indenter) on the bonded-interfaces of the hydrogen-charged samples. The subsurface deformation of the charged sample was compared with that of non-charged sample. Subsequent performance of nanoindentation (with a Berkovich indenter) on the subsurface deformation regime (underneath the macroscopic spherical indentation) revealed that all the hydrogen-charged and non-charged samples experienced the softening behaviour during macroscopic indentation, but the characteristics and degree of the softening was significantly dependent on the hydrogen charging time.