Influencia de los bordes de antifase sobre la temperatura de transformación martensítica en cintas de Cu-Zn-Al.

G. POZO LÓPEZ; A.M. CONDÓ; J.L. PELEGRINA; L. FABIETTI; S. URRETA

Congreso; 10th Inter-American Congress of Electron Microscopy 2009; 2009

The shape memory effect in Cu-Zn-Al alloys is due to a martensitic transformation that occurs in a certain composition range. The use of rapid solidification techniques allows the production of Cu-Zn-Al ribbons with a high degree of homogeneity and with small grain sizes. These ribbons are of great interest due to their possible application as actuators of reduced size.             The martensitic transformation temperature depends on several factors, being the composition and the degree of atomic order the most relevant. The influence of the grain size is not clear. Therefore, in order to distinguish each contribution, it is necessary to analyze them separately.             The degree of order in Cu-Zn-Al alloys is associated to the L21 antiphase boundary density. In the present work, the antiphase boundaries in Cu-Zn-Al ribbons obtained by twin roll casting were studied by transmission electron microscopy using the dark field technique. Samples obtained with different roll speeds and after different thermal treatments were observed. The L21 antiphase boundary density was found to vary between 0.015 nm-1 and 0.09 nm-1.