Physical and Numerical Modeling of Micro-extrusion Behavior of AA3xxx Aluminum Alloy in Cold Roll Bonding

In the presented study, a combination of physical experiments and the finite element method numerical simulations of the micro-extrusion mechanism in solid-state bonding of an aluminum alloy, during cold rolling has been investigated. For better monitoring of the metal flow during deformation and especially for tracking fractured alumina fragments a thick colored oxide layer was deliberately created on the surface of AA3xxx aluminum strips before rolling through the anodizing process. A progressive reduction per pass from 2% to 65% has been implemented in consecutive experiments at constant rolling speeds for corresponding deformation zone geometry its fracture as well as a different range of metal micro-extrusion through the created cracks within the oxide layer. The evolution of the oxide fracture as a function of deformation per pass was systematically evaluated by scanning electron microscopy for each sample. A numerical model of the metal flow called the micro-extrusion has been developed utilizing DEFORM-2DTM software allowing to calculation of the height of the micro-extrusions for given rolling conditions. Depending on the geometry of the crack the local deformation and friction conditions dictated various responses from the metal flowing through the distance between the oxide fragments.