Dynamic Yield Strength and Spall Strength of Polycrystalline Nickel Aluminide

This study reports the results of experimental research on the dynamic yield strength and spall strength of polycrystalline NiAl under shock-wave loading. Wave profiles obtained by laser interferometry are presented. The free surface velocity profiles of NiAl demonstrate shock wave splitting with the formation of a two-wave configuration of elastic and plastic waves, and a spall pulse caused by tensile fracture of the material. The dynamic yield strength and the spall strength are determined as functions of the shock compression amplitude and strain rate in the unloading part of the pulse. The influence of the shock wave amplitude on the stress relaxation behind the elastic precursor front is described.