Work-hardening and ductility of artificially aged AA6060 aluminium alloy

The work-hardening and ductility of an artificially aged AA6060 aluminium alloy were studied based on tensile tests of smooth and notched cylindrical samples. The alloy was tested after three processing steps, each followed by artificial aging. These processing steps were casting and homogenization, extrusion, and cold rolling and heat treatment to obtain a recrystallized grain structure. Subsequent to each of these processing steps, the material was tested after artificial aging to underaged, peak aged and overaged conditions. The true stress-strain curve to failure was determined by use of a laser-based measurement system. The Bridgman correction was applied to estimate the equivalent stress-strain curves, and the work-hardening behaviour was analysed using an extended Voce approach. Fractography was applied to study the failure mechanisms for material exposed to the different processing steps and temper treatments. To evaluate the use of the Bridgman correction and to study the notch strengthening effect observed experimentally, finite element simulations were performed using the Gurson model. The experimental study demonstrates the effects of thermomechanical processing and artificial aging on the stress-strain behaviour and the tensile failure strain of the alloy.