J. Phys. IV France 112 (2003) 561
Effects of martensitic stabilisation in Cu-Al-Be shape memory alloysC.H. Gonzalez, G. Guénin and M. Morin
Institut National des Sciences Appliquées de Lyon, GEMPPM, UMR 5510 du CNRS, bâtiment Blaise Pascal, 20 avenue Albert Einstein, 69621 Villeurbanne, France
Single crystals of a Cu-Al-Be alloy with transformation temperatures above room temperature were submitted to three different thermal treatments: 1 - direct quenching in water at room temperature followed by an annealing, 2 - step quenching and 3 - direct quenching. Measurements realised by differential thermal analysis shows that some results of stabilisation are similar to other copper based alloys. Nevertheless, direct quench in water leads to a double reverse martensitic transformation. Amplitude and tempei-ature of the first transformation depends on annealing time at 100°C. However. the second transformation is always at the same temperature of 265°C. A shape memory effect is also observed for each of these two steps of the reverse martensitic transformation. These results of martensitic stabilisation for the Cu-Al-Be alloy are discussed in terms of thermal treatment influencing on mechanical lock of interfaces by vacancies (pinning), elimination vacancy mechanisms and order-disorder transitions.
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