Shock-compression fabrication of high-temperature superconductor/ metal composite monoliths

Abstract

In spite of the recent spectacular achievements in developing high-temperature (transition temperature T_c ≥ 77 K) superconductivity in systems generically represented by ABa₂Cu₃O_7–x (where A = Y, La, Nd, Sm, Eu, Gd, Ho, Er, Lu)^1,2, it has been difficult to prepare large powder sample batches (≥0.5 kg). More importantly, efforts to consolidate or sinter superconducting powder samples or to place powders (such as Y–Ba–Cu–O) in useful environments or monolithic structures which are not brittle and friable, and the fabrication of high-temperature superconducting products have been frustrating at best³. Based on the process integration of several fundamental principles involving shock-compression science^4,5, we have successfully fabricated composite/laminate monoliths containing shock-compacted, consolidated and bonded Y–Ba–Cu–O superconducting powder channels (with T^c≥90K) in a solid copper matrix⁶. Using ammonium-nitrate-based explosives (with detonation velocities, V_D, adjusted to be ∼1,800 m s^–1), we have progressed from shock-consolidated, superconducting YBa₂Cu₃O₇ powder-channel rings with mean diameters of 4.4cm and 4mm² cross-sections in explosively (implosive shock-wave) clad solid copper matrices, to monoliths from which copper matrix rings have been cut containing shock-consolidated, superconducting YBa₂Cu₃O₇ powder channels with mean diameters of 24 cm (with 2.5 cm width) and cross-sections of 1.85cm².