Crystallographic texturing in Nb3Sn multifilamentary superconducting composites

Abstract

Crystallographic texturing in Nb3Sn composites, fabricated by both the external diffusion and the commercial bronze processes, has been investigated. In the external-diffusion-processed composite the as-drawn texture of the copper matrix contained ca. 55% 〈111〉 and 45% 〈100〉; after recrystallization at 650 °C for 16 h this changed to 70% 〈111〉 and 30% 〈100〉. Tin plating and reaction heat treatment for 40 h at 650 °C eliminated most of the texturing. In a commercial bronze-processed composite a 〈211〉 or 〈221〉 texture was obtained in the as-drawn bronze matrix, and after a reaction heat treatment at 700 °C for 30 h a diffuse 〈100〉 texture was developed. In both composites the Nb3Sn reaction layer exhibited no preferred orientation.