J. Phys. IV France
Volume 05, Numéro C8, Décembre 1995
International Conference on Martensitic Transformations – ICOMAT 95
Page(s) C8-433 - C8-438
International Conference on Martensitic Transformations

J. Phys. IV France 05 (1995) C8-433-C8-438

DOI: 10.1051/jp4:1995865

The γ-ε Martensitic Transformation : A Model for Stress Induced Variant and its Interaction with Grain Boundary

G. Guénin

Institut National des Sciences Appliquées de Lyon, G.E.M.P.P.M., Bât. 502, 69621 Villeurbanne, France

The γ (f.c.c.) to ε (h.c.p.) martensitic transformation occurs through the Shockley a/6<211> faulting every second {111} plane of the f.c.c. structure. A stress induced thin single variant corresponds to a single a/6<2100> faulting vector and leads to a large homogeneous shear (0.35 in amplitude. The tip of such a plate is composed of a set of identical Shockley partial dislocations with large mutual interactions. This work is a presentation of a model which describes the martensite morphology of stress induced ε martensite in shape memory Fe-Mn-Si based alloys. The model includes the formation mechanism of the plate (Seeger' s like) and its growth inside a limited grain. The mutual interaction of Shockley dislocations and their interaction with the grain boundary is semi quantitatively described ; it leads to a lenticular shape of ε martensite thin plates. The model is able to explain the behaviour of this kind of alloys concerning the superelastic effect and the shape memory.

© EDP Sciences 1995