Numéro
J. Phys. Colloques
Volume 43, Numéro C4, Décembre 1982
ICOMAT-82
International Conference on Martensitic Transformations
Page(s) C4-57 - C4-73
DOI https://doi.org/10.1051/jphyscol:1982404
ICOMAT-82
International Conference on Martensitic Transformations

J. Phys. Colloques 43 (1982) C4-57-C4-73

DOI: 10.1051/jphyscol:1982404

LOCALIZED LATTICE INSTABILITY RELATED TO THE NUCLEATION PROBLEM OF MARTENSITE

G. Guénin et P.F. Gobin

Groupe d'Etudes de Métallurgie Physique et de Physique des Matériaux, I.N.S.A., Bât. 502, 69621 Villeurbanne Cedex, France


Abstract
The generalized soft mode is not very convenient to explain the martensite nucleation process. It must be substituted by a localized soft mode approach. The starting point for this approach is the sensitivity of the mechanical stability to the strains. It is first demonstrated that calculations using second and third other elastic constants provide a good approximation to the strain producing the instability. The effects of some particular strain such as "Bain strain" or {110} <[MATH]> in ß phase alloys are reviewed. The soft zones around some specific lattice defects like dislocations and free surfaces are then analyzed. It is shown that large lattice vibrations are localized in these soft zones. An attempt is made to explain the role of the soft zones and associate large vibration to the nucleation process.