Experimental Validation of Quasi-Elastic Response of Metal during Reloading Process

An uniaxial strain experiment of a magnesium alloy (brand:MB2) disk under shock loading and reloading was designed by a wave reflection method. Time-resolved interfacial velocity between the MB2 sample and a LiF window was measured by a VISAR (Velocity Interferometer System for Any Reflection) probe during the dynamic loading. Our result reveals that, under a better test condition with no rarefaction disturbing from the window (present in previous experiments), an elastic-plastic response does exist in the process of reloading from an initial shock state (24 GPa). This validates that the quasi-elastic response of metals under recompression, which had been reported by Asay et al, is an intrinsic character of the materials. Some discussion about the experimental technique for measuring the constitutive parameters of metals at high pressures will be presented also.