MARTENSITIC TRANSITION ENTROPY CHANGE AND ELASTIC CONSTANTS OF Cu-Al-Be ALLOYS

Measurements of the enthalpy ([MATH]H) and entropy ([MATH]S) changes associated with the martensitic transformation of Cu-Al-Be single crystals of different compositions, were performed by differential scanning calorimetry. In addition, the elastic constants of the body-centered-cubic parent phase single crystals were measured as a function of temperature, using the ultrasonic pulse-echo frequency varying - phase detection method, and the value of the elastic anisotropy (A = C44/C') was computed at the martensitic transformation temperature. The results are in good agreement with a theoretical expression obtained according to models previously proposed, which relates [MATH]S to the elastic anisotropy of the parent phase at the martensitic transformation temperature.