Effects of aging parameters on formability of 6061-O alloy

6XXX series aluminum-magnesium-silicon (Al-Mg-Si) alloys are medium strength alloys widely used as automotive body materials. The mechanical properties of these alloys are adjusted by performing age hardening heat treatments. In this research, the effect of aging time on formability of 6061-O alloy is investigated. The formability of the material is evaluated by tensile. Erichsen, and hole expansion tests. Results reveal that formability decreases with increasing aging time. The evolution of the anisotropy, r, with the aging time depends on the direction of probing relative to the texture direction. Yield surfaces predicted using the Hill-90 and Barlat-89 models are plotted using experimental r values for several aging times. Since r changes, these surfaces deform slightly and expand with increasing aging time. (C) 2010 Elsevier Ltd. All rights reserved.