DISLOCATION PINNING EFFECT. A PROBE OF SELF-INTERSTITIAL AND HYDROGEN MIGRATION IN NIOBIUM AND TANTALUM

J. Lauzier , J. Hillairet , A. Vieux-Champagne , J. Baur , H. Schultz

The internal friction and elastic modulus of high purity, dehydrogenated Nb and Ta single crystals were analysed after in situ cold-work and/or electron irradiation at temperatures down to 4 K. In irradiated niobium, a marked dislocation pinning becomes evident at 6 K. Combined with previous resistivity data, this result is taken as evidence of long-range migration of self-interstitials. In tantalum cold-worked at 4.2 K, a large pinning stage takes place during heating between 8 K and 13 K. It Is interpreted in terms of point defect diffusion to dislocatlons. Possibly, minute amounts of hydrogen are involved. Typical activation enthalpies for the migrating defects are between 0.01 and 0.02 eV. Low temperature irradiation in the as-deformed state reveals additional pinning beginning at 6 K, which implies mobile intrinsic interstitials.

Domaines: Articles anciens

J. Lauzier, J. Hillairet, A. Vieux-Champagne, J. Baur, H. Schultz. DISLOCATION PINNING EFFECT. A PROBE OF SELF-INTERSTITIAL AND HYDROGEN MIGRATION IN NIOBIUM AND TANTALUM. Journal de Physique Colloques, 1987, 48 (C8), pp.C8-119-C8-124. ⟨10.1051/jphyscol:1987814⟩. ⟨jpa-00227118⟩