Numéro
J. Phys. Colloques
Volume 43, Numéro C4, Décembre 1982
ICOMAT-82
International Conference on Martensitic Transformations
Page(s) C4-133 - C4-138
DOI https://doi.org/10.1051/jphyscol:1982413
ICOMAT-82
International Conference on Martensitic Transformations

J. Phys. Colloques 43 (1982) C4-133-C4-138

DOI: 10.1051/jphyscol:1982413

BETA-PHASE INSTABILITY AND MARTENSITIC TRANSFORMATION IN Ti-22 a/o Nb ALLOY

P. Hochstuhl1 et B. Obst2

1  Universität Karlsruhe, Institut für Experimentelle Kernphysik, F.R.G.
2  Kernforschungszentrum Karlsruhe, Institut für Technische Physik, F.R.G.


Abstract
The variation of the electrical resistivity with temperature (4 to 300 K) and strain has been measured in solid solution Ti-22 a/o Nb. The experiments have been conducted on a tensile machine equipped with a temperature-variable flow cryostat. Depending on the sample history, the value of the temperature-coefficient of resistivity appears to be abnormal. In the as-quenched condition, the alloy shows a negative dρ/dT in a certain range of temperatures. The resistivity-temperature relation is found to be reversible (no hysteresis) ; variations with ageing time have been observed. The resistance anomaly appears to be closely related to the incipient instability of the ß phase as the system tends towards thermodynamic equilibrium. Polymorphic transformations will produce a kinetic barrier for further ß instability.