ON THE INSTABILITY LEADING TO THE MARTENSITIC-TRANSFORMATION OF CU-ZN-AL SINGLE-CRYSTALS

Cu-Zn Al alloys are known to exhibit shape memory properties when the temperature is varied. This behaviour is directly connected to the martensitic transformation that such materials undergo. If the general characteristics of this transformation are well understood, the nucleation mechanism of the transformation is not completely clear. However, it seems that the residual stresses play a major role in the process of nucleation. As a consequence, the measurement of the nonlinear elastic parameters as a function of temperature for shape memory single crystals may clarify the process of nucleation. Such data are reported in this paper; a model is proposed for the interpretation of the experimental results.