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J. Phys. IV France
Volume 05, Numéro C2, Février 1995
IIIrd European Symposium on Martensitic Transformations
Page(s) C2-367 - C2-372
IIIrd European Symposium on Martensitic Transformations

J. Phys. IV France 05 (1995) C2-367-C2-372

DOI: 10.1051/jp4:1995256

Two Way Shape Memory Springs with Improved Repeatability on Thermal Cycling

H. Bordét and B.G. Mellor

Engineering Materials, The University, Southampton, SO9 5NH, U.K.

The influence of pre-training heat treatments on the amount and repeatability of the two way shape memory (TWSM) effect developed in Cu-Zn-Al shape memory compression springs is studied. Pre-training heat treatments were achieved by flash heating in a fluidised bed for various times at temperatures between 200°C and 450°C. Training was carried out by constraint ageing at temperatures between 100°C and 150°C. The TWSM was assessed by thermal cycling the springs both unloaded and opposed by weights. TWSM was shown to be critically dependent on the flash heating temperature and time and also on the exact procedure used in the constraint ageing training treatment. Scanning electron metallography and Vickers microhardness measurements were used to correlate TWSM with microstructure.

© EDP Sciences 1995