Hot and Cold Tensile Behavior of Al 6061 Produced by Equal Channel Angular Pressing and Subsequent Cold Rolling

Authors

1 Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran

2 Metallic Materials Research Center (MMRC-MA), Malkashtar University, Tehran, Iran

3 Department of Mechanical Engineering, University of Maryland, Baltimore County, USA

Abstract

The full annealing AA6061 aluminum alloy was subjected to severe plastic deformation
via the combination of equal channel angular pressing (ECAP) and cold rolling (CR) in order to
refine its microstructure and to improve its mechanical properties. According to the results of hot
and cold tensile tests, the combination of ECAP and CR significantly affected the final strength
and ductility of studied AA6061. Four passes of ECAP followed by 90% reduction in rolling led to
about 5.4 and 3.15 times increase in the yield and ultimate tensile strengths, respectively. In
addition, the hot ductility and strain rate sensitivity were increased by applying ECAP plus CR.
The changes in mechanical properties were attributed to the enhanced dislocation density and to
the reduced grain size. The results show that a decrease in grains/subgrains size (0.37 μm) and an
increase in the fraction of high angle grain boundaries, exhibited significant effect on the hot
ductility of higher severe plastic deformed sample.

Keywords