ELABORATION AND CHARACTERIZATION OF NEW LOW-TEMPERATURE SHAPE-MEMORY CU-AL-BE ALLOYS

The addition of small concentrations of beryllium to Cu-Al alloy close to the eutectoidal composition leads to a sharp decrease in the marte nsitic transformation temperature, while the composition corresponding to the maximum stability of the beta phase does not change significan tly. The eutectoidal temperature is lowered, but the temperature of be ta solution treatment remains the same. Moreover, there is no change i n the nature of the martensitic transformation (DO3 half arrow right o ver half arrow left 18R). All these properties are very interesting fr om the industrial point of view: whatever value M(s) (''martensite sta rt'') temperature is chosen, the stability of the beta phase is approx imately the same since the alloy is always close to the eutectoidal co mposition. This alloy is therefore a good complement of Cu-Al-Ni alloy for low transformation temperatures (below room temperature) with app roximately the same resistance to ageing. Both one way and two way mem ory effect (TWME) experiments were carried out on the specimens.