Entropy change of martensitic transformations in Cu-based shape-memory alloys
Open Access
- 1 August 1993
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 48 (6), 3611-3619
- https://doi.org/10.1103/physrevb.48.3611
Abstract
We have investigated the different contributions to the entropy change at the martensitic transition of different families of Cu-based shape-memory alloys. The total entropy change has been obtained through calorimetric measurements. By measuring the evolution of the magnetic susceptibility with temperature, the entropy change associated with conduction electrons has been evaluated. The contribution of the anharmonic vibrations of the lattice has also been estimated using various parameters associated with the anharmonic behavior of these alloys, collected from the literature. The results found in the present work have been compared to values published for the martensitic transition of group-IV metals. For Cu-based alloys, both electron and anharmonic contributions have been shown to be much smaller than the overall entropy change. This finding demonstrates that the harmonic vibrations of the lattice are the most relevant contribution to the stability of the bcc phase in Cu-based alloys.Keywords
This publication has 24 references indexed in Scilit:
- Phonon dispersion of the bcc phase of group-IV metals. II. bcc zirconium, a model case of dynamical precursors of martensitic transitionsPhysical Review B, 1991
- Phonon dispersion of the bcc phase of group-IV metals. I. bcc titaniumPhysical Review B, 1991
- Phonon dispersion of the bcc phase of group-IV metals. III. bcc hafniumPhysical Review B, 1991
- Vibrational entropy effects at a diffusionless first-order solid-to-solid transitionPhysical Review B, 1991
- Exactly solvable heterophase fluctuations at a vibrational-entropy-driven first-order phase transitionPhysical Review Letters, 1990
- Phonons and martensitic phase transitions in pure bcc Ti and bcc ZrPhysical Review B, 1989
- Temperature-induced hcp-bcc phase transformation in zirconium: A lattice and molecular-dynamics study based on anN-body potentialPhysical Review Letters, 1989
- Phonon-phonon coupling and the stability of the high-temperature bcc phase of ZrPhysical Review Letters, 1987
- Martensite and equilibrium phases in CuZn and CuZnAl alloysProgress in Materials Science, 1986
- Temperature dependence of the normal vibrational modes of hcp ZrPhysical Review B, 1978