J. Phys. IV France
Volume 05, Numéro C8, Décembre 1995
International Conference on Martensitic Transformations – ICOMAT 95
Page(s) C8-131 - C8-136
International Conference on Martensitic Transformations

J. Phys. IV France 05 (1995) C8-131-C8-136

DOI: 10.1051/jp4:1995815

Landau-Ginzburg Model of Interphase Boundaries in CsCl-Type Ferroelastics due to M-5 Mode Instability : LaAg1-xInx

D.M. Hatch1, P. Hu1, A. Saxena2 and G.R. Barsch3

1  Department of Physics, Brigham Young University, Provo, Utah 84602, U.S.A.
2  Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, U.S.A.
3  Materials Research Laboratory and Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A.

We have constructed a Landau-Ginzburg model of ferroelastic domain walls in the tetragonal phase of CsCl-type intermetallic compounds. This improper ferroelastic phase transition is driven by the condensation of a degenerate zone-edge phonon mode of M-5 symmetry and can be described by a six-component order parameter. Analytic and numerical kink-type soliton solutions for the order parameter profile and the strain distribution are obtained for three different interphase boundaries : a twin boundary and two antiphase boundaries. The stability, merging and splitting of various domain types are also studied. Specifically, a symmetry-allowed product phase of 14/mmm (D174h) symmetry has been experimentally observed in pseudobinary rare earth alloys of composition RAg1-x Inx (R=La, Ce, Pr) and in related systems (YCu, LaCd).

© EDP Sciences 1995