AN EXPERIMENTAL-STUDY OF THE COUPLING BETWEEN THE ORDER-DISORDER TRANSITION AND THE MARTENSITIC-TRANSFORMATION IN CU-AL-BE SHAPE-MEMORY ALLOYS

Order-disorder transitions in Cu-Al-Be alloys have been studied by mea ns of X-ray diffraction measurements, Assuming that different ordered degrees can be ''frozen'' with suitable heat treatments, their effect on the martensitic transformation has been analized by microcalorimetr y. The results indicate a change in the temperature of the martensitic transformation directly related to the change of the order degree: di sordering stabilizes the martensite phase. Other effects observed afte r specific heat treatments have been associated to the vacancies retai ned after the quench, Additional elastic neutron scattering experiment s provide data to fit the temperature changes to a previous proposed m odel.