Analysis of the internal friction spectra during martensitic transformation by a new temperature rate method

The internal friction spectra of a martensitic transformation obtained as a function of temperature with (T) over dot not equal 0, consists of three different contributions: transitory, phase transition, and intrinsic. In order to get a more quantitative information from these internal friction spectra, such as the volume fraction of transformed material, it is necessary to separate the spectra in their different contributions. This paper proposes a new method which allows to analyse the IF spectra. The new procedure is based on the strong dependence of the transitory term on the temperature rate. Thus, the separation of the three different contributions to the IF is completed starting from several IF spectra carried out at different temperature rates. Using this method it is possible to check the validity of the different models proposed in the literature for the explanation of the transitory term. Along with the presentation of the method, its application to a thermoelastic Cu-AI-Ni shape memory alloy is shown. (C) 2000 Elsevier Science S.A. All rights reserved.