Effects of grain shape and texture on the through-thickness yield strength of AA 7055 aluminum alloy plate

The evolution of through-thickness yield strength in AA 7055-T77 aluminum alloy was investigated. The microstructures and textures through the plate were examined and analyzed by the electron back-scattered diffraction (EBSD) technique. The results show that the yield strength increases with increasing distance from the surface layer to the center layer. More equated grains are observed at the surface than that in the center layer, in which the grain boundaries are almost parallel to the rolling direction. And the main texture components near the center are Brass, S, and Copper, while the ones near the surface of the plate are Cube ND and Random. Because the Taylor factor M of the texture components Brass, S and Copper is higher than that of Cube ND and Random when the tensile direction is aligned to the rolling directions, which results in the higher yield strength near the center layer of the plate. The grain shape can also cause the anisotropy of yield strength.