Title :
Spheroidization Effects on the Electrical and Magnetic Properties of Cu-Nb Composites
Author :
Sandim, Maria J R ; Sandim, Hugo R Z ; Stamopoulos, Dimosthenis ; Renzetti, Reny A. ; Das Virgens, Maurício G. ; Ghivelder, Luis
Author_Institution :
Dept. de Engenharia de Materiais, FAENQUIL, Lorena
fDate :
6/1/2006 12:00:00 AM
Abstract :
We report on the microstructure evolution in Cu-15% Nb multifilamentary wires upon annealing and the corresponding effects on their electrical and magnetic properties. During annealing at temperatures higher than 800degC thermal instability mechanisms take place in the microstructure of the Cu-15%Nb composite, leading to spheroidization, followed by coarsening of niobium filaments. Such microstructural changes exert considerable influence on the magnitude of the normal electrical resistivity for the Cu-Nb composite. In addition, the annealing process leads to a double-peak structure in the isothermal DC magnetization curves of the composite, which is strongly dependent on the annealing time. This behavior suggests that the spheroidization kinetics can be obtained from M(H) curves
Keywords :
annealing; copper alloys; electrical resistivity; magnetisation; multifilamentary superconductors; niobium alloys; spheroidizing; thermal stability; Cu-Nb; annealing; electrical resistivity; isothermal DC magnetization curves; magnetic properties; microstructure evolution; multifilamentary wires; niobium filaments; spheroidization effects; thermal instability; Annealing; Electric resistance; Isothermal processes; Kinetic theory; Magnetic properties; Magnetization; Microstructure; Niobium; Temperature; Wires; Cu-Nb composites; electrical resistivity; magnetization; spheroidization;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2005.864287
