Impact of V additions on the microstructure and mechanical properties of Al-6xxx alloy

The automotive industry demands high-performance aluminium alloys, with standard alloys increasingly unable to meet expectations. This study explores the effects of vanadium on the microstructure and mechanical properties of the Al-Mg-Si-Mn-Cu-Cr alloy. DC-cast alloys, with and without vanadium, were homogenised, extruded into crash-box profiles, and heat-treated under varying parameters to achieve T5 and overaged T5 conditions. Tensile and bending tests evaluated mechanical performance, while microstructural analysis revealed that vanadium enhanced grain refinement and precipitation behaviour. Vanadium addition improved elongation from 10.32% to 13.04% with extended heat treatment at 215°C. Bending performance also increased, with a 57% improvement in the underaged condition and a 12.3% increase in the overaged condition, indicating better crash resistance. Microstructural observations confirmed a finer grain structure and uniform secondary phase distribution. These findings suggest that vanadium can effectively enhance the performance of 6xxx series aluminium alloys, making them suitable for demanding transportation applications.