Applying infrared thermography to analyse martensitic microstructures in a Cu–Al–Be shape-memory alloy subjected to a cyclic loading

This study aims at revealing martensitic microstructures that exist in a shape-memory alloy. Infrared thermography was used for this purpose. Experiments were performed on a Cu–Al–Be single crystal which features a pseudoelastic response at ambient temperature. The specimen was first partially transformed to martensite by mechanical loading. Then a small cyclic loading was applied while the temperature evolution on the specimen surface was captured by an infrared camera. Thermal images obtained were then processed to extract two types of quantities: the maps of heat sources produced by the material and the maps of temperature oscillation amplitudes. Two thermomechanical couplings are revealed: the thermoelastic coupling and the latent heat due to the small cyclic movement of austenite–martensite interfaces, thus highlighting the martensitic microstructure distribution in the specimen.