Zr-based metallic glasses Hugoniot under laser shock compression and spall strength evolution with the strain rate (> 10⁷ s^-1)

We investigate the mechanical response of Zr₅₀Cu₄₀Al₁₀ and Zr₆₀Cu₃₀Al₁₀ metallic glasses under laser shock compression to reproduce hypervelocity impact conditions such as high longitudinal stresses and high strain rates in an unknown range of 10⁶−10⁷s⁻¹. Hugoniot curves and strength parameters (spall strength and strain rate) are obtained from free surface velocity profiles and compared with previous studies on the mechanical behaviour of Zr-based metallic glasses under plate impact experiments. We established Hugoniot curves for both compositions up to 100 GPa, corresponding to a particle velocity of 1.8 km/s, and consistent with literature up to 75 GPa. Concerning the strength parameters, we studied the evolution of the spall strength with the strain rate and obtained data unreached up to now from 1.7×10⁶s⁻¹ to 2.7×10⁷s⁻¹. This range of data correspond to strain rates of hypervelocity impacts of small debris (≈0.1−1mm) on space infrastructure shields. Moreover, we highlight a strong dependency of the spall strength with the strain rate starting from 2×10⁶s⁻¹. Indeed, the spall strength increases from 2.6 GPa, close to its quasi-static tensile strength value, up to 13.6 GPa.