Strain-Induced Surface Roughening in Polycrystalline Aluminum Alloys. Experiment and Simulation

Micro- and mesoscale surface roughening in as-received and rolled aluminum alloys under uniaxial tension is investigated experimentally and numerically. Experiments were conducted on the evolution of the surface roughness in as-received alloys and those produced from a rolled sheet cut across and along the rolling direction. Three-dimensional polycrystalline models of equiaxed and elongated grain structures were developed and implemented in finite-element and finite-difference calculations. Constitutive models of grains were constructed using anisotropic elasticity and crystal plasticity theory. The roughness patterns have been found to vary with the microstructure and texture of the materials and with loading conditions, even though all test specimens have certain features in common. The mesoscale surface undulations observed are shown to be much more pronounced in the rolled specimens, whereas the microscale surface relief attributed to intragranular strains is well-defined in the as-received non-textured polycrystals.