Thermomechanical Behaviour of Monocrystalline Cu-Al-Be Shape Memory Alloys and Determination of the Metastable Phase Diagram

A. Hautcoeur , A. Eberhardt , E. Patoor , M. Berveiller

Stress-strain behaviour of monocrystalline Cu-Al-Be alloy was investigated by uniaxial tensile tests in a temperature range between -70°C and +160°C. Four kinds of typical behaviours were examined in this study. Main interest was the determination of the σ-T diagram obtained from the σ- ε curves. This metastable phase diagram is comparable to the Cu-Al-Ni one. Isothermal mechanical cycling was made at 6% strain up to 1500 cycles. As a result, a deterioration of the superelastic behaviour was found. A thermal flash allows to partially recover this behaviour. Rupture tests performed at a temperature above 120°C have shown the critical stress above which either brittle fracture of α' martensite occurs or plastic deformation of β phase takes place. Finally, comparative tests have been made between a single crystal, a polycrystal with small grains and a polycrystal with columnar structure (bamboo-type).

Domaines: Articles anciens

A. Hautcoeur, A. Eberhardt, E. Patoor, M. Berveiller. Thermomechanical Behaviour of Monocrystalline Cu-Al-Be Shape Memory Alloys and Determination of the Metastable Phase Diagram. Journal de Physique IV Proceedings, 1995, 05 (C2), pp.C2-459-C2-464. ⟨10.1051/jp4:1995270⟩. ⟨jpa-00253656⟩