Materials Science and Engineering: A ( IF 4.652 ) Pub Date : 2020-01-07 , DOI: 10.1016/j.msea.2020.138928 Henrique Martinni Ramos de Oliveira; Hervé Louche; Estephanie Nobre Dantas Grassi; Denis Favier
This study analyses the thermomechanical tensile behaviour of a cold drawn Ti-50.9at.%Ni wire submitted to heat treatment at 598 K for 30 min, which is below the recrystallization temperature (623 K). Such low temperature heat treatment induces a superelastic loop without a stress plateau. However, the absence or weakness of peaks on its differential scanning calorimetry prevents the determination of specific latent heat. This is a common effect of nanostructured materials such as superelastic wires. A method using strain and temperature field measurements was developed and used to determine thermal power and thermal energy during superelastic tensile tests through a heat balance. From these results and using a thermodynamic approach, forward and reverse specific latent heat and the martensite fraction are estimated as a function of strain and stress.