J. Phys. IV France 11 (2001) Pr8-451-Pr8-456
Multiple martensitic transformation induced by coherent precipitation in NiTiCo melt spun ribbonsPh. Vermaut1, 2, M. Larnicol2, M. Hÿtch1, P. Ochin1 and R. Portier1, 2
1 Centre d'Études de Chimie Métallurgique, UPR 2801 du CNRS, 15 rue Georges Urbain, 94407 Vitry-sur-Seine, France
2 Laboratoire de Métallurgie Structurale, École Nationale Supérieure de Chimie de Paris, 11 rue Pierre et Marie Curie, 75231 Paris, France
A study of a multiple martensitic transformation observed in melt spun ribbons cast with a relatively low melt temperature is presented. Transmission electron microscope (TEM) investigations allow the identification of fine plate-like precipitates as a metastable Ti2Ni phase. Analysis of high resolution microscope (HREM) images reveals the presence of a strain field in the matrix surrounding the precipitates which promote the martensitic transformation. Grow and loss of coherency of these precipitates coincides with disappearance of the higher temperature martensitic transformation. Attribution of the multiple transformation to this precipitation is discussed.
© EDP Sciences 2001