Article ID Journal Published Year Pages File Type
7883299 Acta Materialia 2012 8 Pages PDF
Abstract
The magnetic contribution to the martensitic transformation entropy change plays a crucial role in the transition properties of metamagnetic shape memory alloys. This contribution leads to a common dependence of the total entropy change at the structural transformation, ΔStr, on the normalized temperature difference δAtr=(TCA-Ttr)/TCA (where TCA is the Curie temperature of the austenitic phase and Ttr is the transformation temperature) whose main feature is a decrease in ΔStr with increasing δAtr. A phenomenological model based on a Bragg-Williams approximation has been proposed to describe the observed behaviour in terms of the evolution of the magnetic contribution to the total entropy change. The proposed approximation provides a good fitting between predicted and experimental entropy changes obtained for different Ni-Mn-based alloy systems.
Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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