Effect of alloy composition and heat treatment onmechanical performance of 6xxx aluminum alloys
(1. ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering,
Monash University, VIC 3800, Australia;
2. Centre for Advanced Hybrid Materials, Department of Materials Engineering,
Monash University, VIC 3800, Australia)
Monash University, VIC 3800, Australia;
2. Centre for Advanced Hybrid Materials, Department of Materials Engineering,
Monash University, VIC 3800, Australia)
Abstract: The effect of alloy composition and heat treatment, including natural ageing and pre-ageing, on the mechanical performance of eight 6xxx alloys designed with systematically varying Si, Mg and Cu contents was studied. The results show that not only the alloy composition and heat treatment before forming influence the formability, but also they have an effect on the paint bake response of the alloys. Increasing the alloy Si content, decreasing Mg/Si ratio and adding 0.3% Cu (mass fraction) were generally found to improve the tensile ductility and formability of the alloys studied, while pre-ageing was found to decrease these properties. A full property profile of these alloys in terms of strength, tensile ductility, work hardening, strain rate sensitivity, forming limit and paint bake response was presented.
Key words: 6xxx aluminum alloys; automotive sheet; heat treatment; formability; mechanical performance