Analysis of the Intrinsic Anelastic Contribution During the Martensitic Transformation

Abstract
Anelastic techniques have been widely used in characterizing the martensitic transformation in shape memory alloys. The Interna1 Friction (IF) spectra obtained include three different contributions : phase transition, transitory and intrinsic. The intrinsic component must be removed in order to study the two fist contributions, which are directly related to the martensitic transformation. This allows us to evaluate, among other parameters, the transformed volume fraction. Nevertheless, there is not any standard procedure to subtract this background. In this work, we propose a systematic method to remove the intrinsic component of IF spectra for different frequencies and heating rates, where the transitory component is the most important one. The method is based on the relationship between both the intrinsic and transitory components with the martensitic transformed fraction. The application to a thermoelastic Cu-Al-Ni shape memory alloy is shown.