The respective influences of grain size and texture on the formability of a 1050 aluminium alloy

Abstract

In order to clarify the relative influences of texture and grain size on the plastic response of a 1050 Al alloy, some tensile tests have been performed after various annealing treatments (designed to obtain different grain sizes) and initial and final textures have been measured. A micro–macro model has then been used in order to suppress the effect of texture from the macroscopic stress–strain curves. As for the description of textures, it has been shown that most of the obtained textures after annealing can be described as a mixture of rolling and recrystallisation textures (containing mainly the so-called Cube, Brass and Goss orientations) and that there is no clear correlation between texture intensity and grain size; after deformation, the Brass component is reinforced at the expense of the Goss orientation, whereas the evolution of the Cube component depends on the initial scatter around the various components. Concerning the tensile curves, it is observed first that the Hall–Petch relationship is not always verified (the smaller the grain size, the higher the yield stress) when the conventional stress/strain curves are examined. When the effect of texture is suppressed from these curves and ‘microstructural’ stress/strain curves are plotted, the Hall–Petch relationship becomes verified and the curve crossing phenomenon, sometimes observed, disappears. It can thus be concluded that the grain size is the only microstructural feature affecting the yield stress and that the hardening evolution is more or less independent of the texture evolution.