Analysis of mechanical behaviour of AA6082-T6 sheets deformed at low temperatures

High-resistant 6xxx series aluminium alloy sheets are more and more used in the automotive industry thanks to their high strength-to-density ratio, which allows the vehicles weight reduction; however, they can be hardly deformed at room temperature due to their reduced formability, while forming at elevated temperature usually leads to a reduction of the sheet strength, making necessary post-forming heat treatments. The present research study aims at evaluating the mechanical behaviour of AA6082-T6 sheets deformed in the temperature range between 300°C and -100°C, to assess the possible increase of both ductility and strength when deforming below room temperature. Uniaxial tensile tests were carried out at different temperature regimes and then, ductility, strength and failure mode were evaluated. Surface integrity after mechanical processing was investigated in terms of microstructures and nano-hardness measurements. Results confirmed that the strength and ductility of aluminium alloys improved at temperature decrease. Additionally, sheets deformed at low temperature were characterized by enhanced nano-hardness.