The spall strength and hugoniot elastic limit of iron-nickel alloys of meteoritic origin

The results of measurements of critical fracture stresses (spall strength) and parameters of the elastic-plastic transition of samples of four iron meteorites: Chinga, Sikhote-Alin, Seymchan and Dronino under shock wave loading are presented. The experiments were carried out on a pneumatic gun at a shock compression intensity of $\sim$5.5 and $\sim$11 GPa and a strain rate before spall fracture of $\sim$10$^5$ s$^{-1}$. The strength characteristics were determined from the analysis of complete wave profiles recorded during the loading of samples using a VISAR laser interferometer with high spatial and temporal resolution. It was found that the samples of the Sikhote-Alin meteorite demonstrated the highest Hugoniot elastic limit of all the tested samples, which was 1.6 GPa. The highest value of the spall strength (3.92–4.04 GPa) was measured on the samples of ataxite Chinga. A comparative analysis of the strength characteristics of the studied meteorites with the strength properties of the iron-nickel alloy H6, which has a composition close to meteorite, as well as with a number of modern structural steels for various purposes, was carried out. The comparison has shown that the strength characteristics of iron meteorites under these loading conditions are close to the strength properties of the steels and iron-nickel alloys of terrestrial origin.