Controlled grain size distribution and refinement of an EN AW-6082 aluminium alloy

An EN AW-6082 aluminium alloy was subjected to incremental deformation by a new process named gradation rolling. The process has been used to generate a grain size distribution in a rod-shaped billet. A grain size gradient ranging from coarse-grained in the billet core to ultrafine-grained at the surface of the billet can be obtained. The grain size distribution has been confirmed by electron backscatter diffraction showing the grain refinement related to the true strain. The fibre texture of the base material has been transformed to a rolling texture in the surface region. This results in strain-hardening and grain-boundary strengthening in the surface region (130 HV0.5) as compared to the unchanged core material (110 HV0.5).