Optimization of the Microstructure of Nb3Sn Layers in Superconducting Composites

This paper presents a brief review of the study of the evolution of the microstructure of superconducting Nb3Sn layers prepared using different regimes of diffusion annealing in multifilamentary conductors of different designs made by the bronze method and by the internal-tin-source method. The work is based on original investigations of the authors and on the most significant results published by others. In this paper we consider the influence of the manufacturing method, alloying, geometry of wires, and heat treatment modes on the formation of Nb3Sn layers, their structure and morphology, and, as a consequence, on the current-carrying capacity of multifilamentary superconductors.