Microstructure and Properties of Simultaneously Processed Nb-Ti and Nb-Ti-Ta Superconducting Wires
The evolution of the microstructure (sub-band size, α phase precipitation) of a Nb-47.1wt%Ti and of a Nb-45 wt%Ti-15wt%Ta alloys is followed during their simultaneous thermomechanical processing. The effects of a Ta addition, cold work prestrain, and of the temperature and duration of heat treatments on the volume fraction, size, density and localization of the particles of α phase are especially documented. Widmanstätten α strengthens the NbTiTa alloy and exerts a deleterious influence on Jc. Some solutions are proposed to these harmful effects. At last, the relationships describing the dependence of the α phase distribution on strain are also considered.
KeywordsHeat Treatment High Volume Fraction Total Volume Fraction Deleterious Influence Superconducting Wire
Unable to display preview. Download preview PDF.
- 2.D.G. Hawksworth, and D.C. Larbalestier, “Enhanced values of Hc2 in Nb-Ti Ternary and Quaternary Alloys”, in “Advances in Cryogenic Engineering” 26 (1980), p. 479.Google Scholar
- 4.E.W. Collings. “Applied Superconductivity”, Plenum Press, New York (1986).Google Scholar
- 5.E. Gregory, T.S. Kreilick, F.S. von Goeler, and J. Wong, “Preliminary Results on Properties of Ductile Superconducting alloys for Operation to 10 Tesla and above”, Proc. ICEC12, Southampton [U.K.] (1988), p. 874.Google Scholar
- 8.C.E. Bruzek, “Optimisation de la Microstructure de Composites Supreaconducteurs Nb-Ti”, Doctoral Thesis, Université de Lille I (1993).Google Scholar
- 12.G.K. Zelenskiy, A.V. Arsent’ev, A.P. Golub’, V.E. Klepatsky et al., “Inluence of Thermomechanical Working Schedules on Structure and Properties of HT-50 and HT-55 Superconductors Alloys”, in: “Advances in Cryogenic Engineering, Materials” 36A (1989), p. 295.Google Scholar