Effect of asymmetric rolling on the microstructure and mechanical properties of wrought 6061 aluminum

Asymmetric rolling is achieved usually by deforming a material through rollers of the same diameter driven at different velocities or via rollers of different diameters but the same velocity. Asymmetric rolling has become important particularly because it can be used to modify the microstructure and in turn improve the mechanical properties of most materials. This is especially true for various metals such as iron, magnesium and aluminum alloys. The objective of this of this research was to investigate the effects of the core processing parameters of interest (roller velocities, velocity ratio, rolling direction, starting thickness of specimen and extent of reduction) on aluminum alloy AA6061 (Al-0.6Si-1.0 Mg). Experimental findings indicated that ASRed specimens exhibited superior tensile properties to symmetrically rolled counterparts provided that the net reduction was achieved in a minimum number of passes. Conversely, no significant gains were recorded in the mechanical properties due to increases in roller velocities or altering the rolling direction. Comparisons of the resultant microstructures within asymmetrical and conventionally rolled counterparts as assessed through electron back scatter diffraction (EBSD) are also presented. The undeformed base metal revealed the presence of a cubic texture {100} < 001 >. This texture however evolved into shear {111} < 110 > and brass {110} < 112 > texture components in specimens subjected to asymmetric (VR = 2.2) and symmetric rolling respectively.