Nucleation of austenite in mechanically stabilized martensite by localized heating

JOURNAL OF ALLOYS AND COMPOUNDS

卷:577

Article; Proceedings Paper

Ball, J. M.¹  Koumatos, K.¹  Seiner, H.² 

[1] Math Inst, Oxford Ctr Nonlinear PDE, Oxford OX1 3LB, England

[2] Inst Thermomech ASCR, Prague 18200 8, Czech Republic

关键词: Phase transitions;    Shape memory;    Microstructure;    Young measures;    Quasiconvexity;   

DOI  :  10.1016/j.jallcom.2011.11.070

来源: Elsevier

【 摘 要 】

The nucleation of bcc austenite in a single crystal of a mechanically stabilized 2H-martensite of Cu-Al-Ni shape-memory alloy is studied. The nucleation process is induced by localized heating and observed by optical microscopy. It is observed that nucleation occurs after a time delay and that the nucleation points are always located at one of the corners of the sample (a rectangular bar in the austenite), regardless of where the localized heating is applied. Using a simplified nonlinear elasticity model, we propose an explanation for the location of the nucleation points, by showing that the martensite is a local minimizer of the energy with respect to localized variations in the interior, on faces and edges of the sample, but not at corners, where a localized microstructure can lower the energy. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free