Texture Characterization of Pb and Pb-62%Sn alloys deformed by ECAE

RAÚL EDUARDO BOLMARO, HEINZ-GÜNTER BROKMEIER, BERND SCHWEBKE AND WEI MIN GAN

2008-10-20/2008-10-27

245-246

Física

Metalurgia

ECAE has been one of the most prolific techniques in the study of severe deformation on metallic alloys. Severe deformation on low melting temperature alloys has been scarcely studied due to the high dynamic recrystallization effects they usually present. Previous ECAE deformation experiments performed in a 120o tool at room temperature in pure Pb and near eutectic composition Pb-62%Sn alloy showed the existence of such recrystallization effects. The results showed a striking rotated cube texture that was explained by modelling a recrystallization behaviour of the kind known as Geometrical Dynamic Recrystallization. On the intended experiments we attempt to complement those results by measuring pure Sn samples. The samples were passed 5 times in a route A. Textures should give a guide of the expected behaviour for the composite Pb-62%Sn sample. Together with the pure Pb results the experiments should give an idea about the dragging force exerted from one phase on the other during large deformation processes. Due to the high absorption presented by Sn and the soft nature of the surface that difficult its proper polish for X-rays, the textures need to be measured by neutron diffraction.             The proposed experiment consists on the measurement of at least four pole figures for each sample, (200), (101), (220) and (211), with the purpose of whole analysis of texture and calculation of the due Orientation Distribution Function. A total of 24 pole figures would be necessary for completely characterize texture evolution for as received and after deformation textures.