Seventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. Colloques 42 (1981) C5-1091-C5-1096
INTERNAL FRICTION AND YOUNG'S MODULUS OF Nb3Sn BETWEEN 6 AND 300 KB. Faucher1, J.F. Bussière1, C.L. Snead1, Jr.2 et M. Suenaga2
1 Institut de génie des matériaux, Conseil national de recherches Canada, 750, rue Bel-Air, Montréal, Québec, Canada, H4C 2K3
2 Brookhaven National Laboratory, Upton, New York, 11973, U.S.A.
Young's modulus and internal friction were measured in polycrystalline NB3Sn between 6 and 300K. Below the martensitic transformation temperature a large rise in internal friction is observed, in agreement with recent observations. In this temperature range, the internal friction is found to be nearly independent of frequency, a behavior consistent with stress-induced wall motion between domains of the tetragonal phase as the main source of relaxation. Internal friction peaks observed at 140 and 260K in Nb/Nb3Sn composite tapes are tentatively attributed respectively to an α peak in Nb and hydrogen in the Nb3Sn layer. Annealing at 750 °C for 1/2h is found to decrease the transformation temperature from 49 to 40K, and to modify the softening of Young's modulus in this temperature range. Young's modulus at 6K is 46% of room temperature value and is unchanged by the annealing treatment.