Interaction between martensitic structure and defects in β ↔ β′ + γ′ cycling in CuAlNi single crystals. Model for the inhibition of γ′ martensite

✍ Scribed by R. Gastien; M. Sade; F.C. Lovey

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 252 KB
• Volume: 56
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.12.005

✦ Synopsis

The authors have previously reported an estimate of the energy associated with the inhibition effect of c 0 martensite after b M b 0 + c 0 cycling in CuAlNi single crystals. In this paper, a microscopic model is proposed to explain the c 0 inhibition, related to the localized interaction between a dislocation array and the twinned c 0 structure. Dislocations with Burgers vector [1 0 0] b and line direction [1 1 1] b in an isotropic b matrix are considered. The model takes into account the interaction between the martensitic stress-free transformation strains and the stress field created by the dislocation arrays. It is shown that the interaction is different for each twin-related variant in the c 0 martensite. The energy necessary to maintain the right volume relationship of the twinned c 0 variants to produce an undistorted b/c 0 habit plane is defined as the inhibition energy. A value of around 12 J mol À1 was obtained, which is in reasonable agreement with experimental results.