The crystal geometry of the tensile deformation of cube-texture aluminum

The crystal geometry of the tensile deformation of cube-texture super-pure aluminum strip has been studied primarily by analysis of tensile test data on specimens cut to correspond with various crystallographic directions and also with parallel structural examination. The results, which were in general agreement with those previously obtained with cube-texture copper, are of interest since aluminum has stacking fault energy intermediate between copper and nickel but has a significantly lower degree of elastic anisotropy. As with copper and nickel the limit of uniform elongation in any direction in the plane of the strip and associated lattice rotation can be predicted in terms of unit slip or stacking fault displacements in appropriate proportions, although minor adjustments are involved in the case of aluminum. The main difference in behaviour from copper and nickel arising from the lesser degree of anisotropy is the abnormally low limiting elastic strain energy for extension near [001] directions. This is associated with the development of secondary [101] (01) slip traces which appear after about 5% extension.