Abstract
The martensitic transformation was investigated in a set of twin roller melt-spun Cu–Zn–Al shape memory alloys, solidified at tangential wheel speeds between 20 and 40 m/s. The resulting microstructures were analyzed using X-ray diffraction, optical and transmission electron microscopy techniques. The characteristic martensitic transformation temperature, M S, was determined for each condition by conventional resistometric methods. The ribbons are homogeneous in shape and for each quenching rate they exhibit a quite uniform M S temperature. By proper thermal treatments, the different factors affecting M S could be separately examined and from temperature measurements, the contribution of L21 antiphase boundaries evaluated. A calculation of this contribution using pair interchange energies is in good agreement with the experimental results.
Acknowledgements
This work was supported by the ANPCyT, CONICET, CNEA, Universidad Nacional de Cuyo and Universidad Nacional de Córdoba, Argentina. Fruitful discussions with Drs. M. Ahlers, F.C. Lovey and A. Yawny are gratefully acknowledged.