Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-369-Pr8-374
DOI: 10.1051/jp4:2001862

The effect of prestrain on stress assisted two way shape memory effect in a Ni₄₅Ti₅₀Cu₅ alloy

L. Omodei¹, G. Gomarasca² and G. Airoldi<sup>2, 3

1</sup>  Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milano, Italy
²  Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via R. Cozzi 53, 20125 Milano, Italy
³  Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via R. Cozzi 53, 20125 Milano, ltaly

Abstract
Stress Assisted Two Way Memory Effect (SATWME) and Electrical Resistance (ER) have been investigated on a Ni₄₅Ti₅₀Cu₅ alloy preliminarily prestrained in martensite to modify the critical stress for slip. Different prestrain levels have been applied. ER vs ε during SATWME follows an almost linear relationship across the transformation range : the plastic deformation accumulated during cycling generally increases, but the figure of ε_p lowers with increasing the preliminary prestrain. Even the highest applied prestrain ( 15%) does not allow to eliminate the build up of plastic strain in each cycle. Different procedures to modify the critical stress for slip must be envisaged.

© EDP Sciences 2001