Severe plastic deformation of 6061 aluminum alloy tube with pre and post heat treatments

In this work, the 6061 aluminum alloy tubes are severely deformed through a novel method called Tube Channel Pressing (TCP). The ability of this process in improving mechanical properties, grain refinement and microstructural changes of the alloy with different heat treatments before and after TCP process is investigated. Results show that TCP has notable effect on grain refinement and decreases crystallite size of solid solution treated aluminum 6061 material to 52 nm after equivalent strain of 3.09 which is comparable with the measured data from other SPD processes. The strength of the specimens aged before TCP is higher than that of those aged after TCP. The specimens artificially aged after TCP show more sharp grain boundaries than those of others and lower dislocation density in grain interiors. Also, aging before TCP leads to finer precipitations than those formed in aging after TCP.