An Improved Impactor Design for Eliminating Spallation in High-Impedance Flyers During Hypervelocity Launch

Spallation in a high-impedance tantalum flyer was confirmed by using a specially designed hypervelocity launch (HVL) experiment, thereby indicating that the conventional flyer was unsuitable for equation of state (EOS) research on materials under ultra-high pressure. Based on the analysis and interpretation of the experimental data and the spallation’s reproduction via a high-fidelity detonation and shock (HDS) wave code, two possible methods to eliminate the spallation were proposed: (1) changing the impactor structure, which could greatly reduce spallation, and (2) altering the impactor material, which could completely eliminate the remaining spallation. We conducted a set of HVL experiments with an improved impactor design in which a high-impedance tantalum flyer was accelerated up to 10 km/s, and no spallation was found, demonstrating the effectiveness of the improved method for performing EOS research on materials under pressures of terapascals loaded by a three-stage light gas gun.