Thermo-mechanical Phase Transformations in Shape Memory Alloys: A Study by Texture Analysis Techniques

E SOBRERO, C; A DRUKER,; A ROATTA,; J MALARRÍA,; G BROKMEIER, H; RAUL EDUARDO BOLMARO

Foz do Iguaçu

Congreso; 17o Congresso Brasileiro de Engenharia e Ciência dos Materiais- CBECIMAT.; 2006

Shape Memory Alloys (SMA) behavior, as many other materials science problems, can be studied at different scales or levels. Texture information provides macroscopically integrative information about the orientation of phases after any thermo-mechanical processing. Texture measurements by X ray and neutron diffraction are superb tools to understand texture development by plastic slip and simultaneous stress and thermal induced phase transformations. First technique is appropriate to evaluate texture heterogeneities while the second one is best suited for measuring bulk textures representative of the average material behavior. SMA transformations proceeds by variants selection and selected variants have been connected in the literature with different phenomena. In the current paper we present experimental and simulation results attempting to discern between the different transformation driving forces. The materials include Fe-Mn-Si alloys and Al-Cu-Ni alloys. The simulations were performed by using polycrystalline self consistent methods for the plastic deformation processes combined with phase transformation codes.