Influence of solutes and second phase particles on work hardening behavior of Al 6063 alloy processed by cryorolling

The effect of solutes, coarse and fine precipitates on work hardening rate and microstructure refinement of cryorolled Al 6063 alloy at different strains was investigated by employing hardness measurements, tensile tests, DSC, XRD, EBSD and TEM characterizations in the present work. The presence of solute in solid solution exhibits a stronger effect on the work hardening of the materials during cryo rolling than the presence of non-coherent and coherent second phase particles. The fine precipitates are sheared and dissolved at a cryorolling strain of 2.3, while the coarse precipitates remain unaffected. The work hardening rate of solutionized material is not saturated even at a cryorolling strain of 2.3, while it is saturated at this strain for the precipitated material. The severe strain induced during plastic deformation of Al 6063 alloy produces ultrafine microstructures with improved strength and hardness. The ageing treatment of the solutionized material after cryorolling at a strain of 2.3 has improved its strength and ductility significantly as compared to precipitated materials due to the precipitation hardening and grain coarsening mechanisms, respectively.