Influence of hot rolling on mechanical properties anisotropy of 6061 aluminum alloy

The influence of change of the hot rolling velocity modes on the mechanical properties of plates of the Al-Mg-Si system aluminum alloy 6061 was studied. The hot rolling was performed in two modes: at the smallest time and at the decreased rolling velocity. After hot rolling the samples were selected from the central part of the strips to determine the standard characteristics describing the mechanical properties of the material: ultimate tensile strength, yield strength and elongation. The obtained values revealed anisotropy of the strength properties. The strength properties in all cases were maximal across the direction of rolling and minimal at an angle of 45º to it. The decrease of the rolling velocity led to higher hardening. The plastic properties of the plate were nearly isotropic. The orientation analysis based on the Electron Backscatter Diffraction (EBSD) showed that the clearly defined crystallographic texture was observed regardless the hot rolling mode. The main components of the texture were the orientations: two from {110}, two from {112}, and also (001)[010] and (110)[001]. By means of the software of the Oxford Instruments analysis system the Taylor factors for axial tension that represents the crystallographic characteristics of the relative strength of the material were calculated. The obtained values of the Taylor factors for the samples selected for the mechanical tests proved that anisotropy of the mechanical stress characteristics of the hot rolled aluminum plate mainly depend on the texture of the material, the indicator of which was a Taylor factor averaged according to the crystallographic orientations.