Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-357-Pr8-362
DOI: 10.1051/jp4:2001860

Martensitic transformation and microstructure of rapidly solidified Ti_50-xNi₂₅Cu₂₅Zr_x shap memory alloys

L. Litynska¹, Ph. Vermaut^{2, 3}, J. Morgiel¹, J. Dutkiewicz¹, P. Ochin³ and R. Portier<sup>2, 3

1</sup>  Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, ul. Reymonta 25, 30-059 Krakow, Poland
²  Laboratoire de Métallurgie Structurale, École Nationale Supérieure de Chimie de Pans, 11 rue Pierre et Marie Curie, 75231 Paris, France
³  Centre d'Études de Chimie Métallurgique, UPR 2801 du CNRS, 15 rue G. Urbain, 94400 Vitry-sur-Seine, France

Abstract
Addition of Zr up to 10 at% to Ti_50-xNi₂₅Cu₂₅Zr_x alloys has been used to elaborate melt spun ribbons. It has been found that low Zr content increase the glass forming ability of the alloy with a maximum at 2.5 % where the ribbon is almost fully amorphous. Above 2.5 at% a second crystalline phase occur which prevent martensitic transformation even in thermal treated samples. After crystallization, bimodal grain size distribution in low Zr content ribbons lead to a two-stage martensitic transformation. A decrease of the transformation temperature is observed with increasing Zr content. The increase of the martensitic transformation temperatures during aging is attributed to a plate-like precipitation.

© EDP Sciences 2001