Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-119-Pr8-124
DOI: 10.1051/jp4:2001821

Effect of hydrostatic pressures on thermoelastic martensitic transformations

D.L. Beke¹, L. Daroczi¹, C. Lexcellent² and V. Mertinger<sup>3

1</sup>  Department of Solid State Physics, University of Debrecen, P.O. Box 2, 4010 Debrecen, Hungary
²  Laboratoire de Mécanique Appliquée Raymond Chaléat, UFR Sciences et Techniques, Université de Franche Comté, 24 chemin de I'Epitaphe, 25030 Besançon, France
³  Department of Physical Metallurgy, Institute of Material Science, University of Miskolc, 3515 Miskolc-Egyetemváros, Hungary

Abstract
Supposing that - according to the Clausius-Clapeyron equation - the volume change of the transformation is responsible for the pressure dependence of the equilibrium temperature T_o, and that the elastic energy term, e_o, corresponding to the martensite start, M_s (and austenite finish, A_f) temperatures, differs from zero as well, the pressure dependence of the elastic and dissipative energy terms of the martensitic and reverse transformations can be separated. It is illustrated by the example of our experimental results for the pressure effect on the transformations in Cu-22at%Zn-12at%Al-1at%Mn [l] as well as in near equiatomic NiTi shape memory alloys [2]. The elastic energy term, e_o, showed different behaviour in the low-pressure range for samples of different pre-history, while at high pressures the pressure dependence of the elastic and dissipative terms showed a more general trend.

© EDP Sciences 2001