Optimization of heat treatment cycle for cast-Al6082 alloy to enhance the mechanical properties

Abstract

The present study focused on optimising the heat treatment cycle for the Al6082 alloy, which is commonly used in the aerospace, automotive, and construction industries. The optimisation process consisted of two steps: optimising the solution and artificial ageing treatments. The as-cast Al6082 alloy samples were solutionised at 480 °C, 495 °C, and 510 °C for 6, 8, and 10 h, respectively, and quenched in paraffin oil at room temperature (RT). The optimal solution treatment was at 495 °C for 8 h. The optimisation of artificial ageing treatment of the optimal solution-treated samples was performed at temperatures of 160 °C, 175 °C, 190 °C, 205 °C, and 220 °C for 4, 6, and 8 h, respectively. Microstructural analysis, mechanical characterisation, i.e. (tensile strength, % elongation, hardness, and impact strength), and fractography analysis of tensile samples were carried out. The results showed that the optimal ageing cycle was obtained at 205 °C for 6 h. Optimised conditions improved tensile strength (154 MPa to 280 MPa) and hardness (65 BHN to 102 BHN) while slightly increasing the impact energy. However, the % elongation decreased. The study emphasises the importance of optimising the heat treatment cycle to meet the desired properties and application requirements of the Al6082 alloy.