High dynamic pressure is used to synthesize metastable superconducting materials and to process superconductors into practical form. Specimens are subjected to shock pressures in the range 0.1-1 Mbar, temperatures up to several 1000 K and quenches at rates up to 1012 bar/s and 109 K/s. Shock waves are generated by impact of projectiles accelerated up to 3.5 km/s by the LLNL two-stage light-gas gun. Recovered specimens are characterized for superconductivity and structural properties. The gas gun, specimen recovery fixture, and phenomenology of the technique are described. Results are reviewed and include a quenched solid-solid phase transition (A15 Nb3Si); amorphous, fine-grained, and multiphase materials produced by shock-induced melting of powders and subsequent rapid solidification; and the shock-compaction in a metal matrix of thin powder layers of high-Tc oxides mixed with metal. The latter is a potential method for fabricating superconducting wire, which could be scaled to long lengths using explosives.
W. J. Nellis,
M. B. Maple,
T. H. Geballe,
"Synthesis Of Metastable Superconductors By High Dynamic Pressure", Proc. SPIE 0878, Multifunctional Materials, (3 May 1988); doi: 10.1117/12.943949; https://doi.org/10.1117/12.943949