Post-fire mechanical properties of aluminum alloy 6082-T6

Abstract

The post-fire mechanical performance of aluminum alloys is a key parameter for residual structural behavior evaluation, repair and reinforcement design of aluminum alloy structures. In this paper, the post-fire residual mechanical behavior of aluminum alloy 6082-T6 under different heat-treatment temperatures and cooling modes, including elastic modulus, yield strength, ultimate strength, percentage elongation after fracture, Vickers hardness value and microstructure, are obtained by 50 standard tests. Test results indicate that Stress-strain curves and mechanical properties can be divided into 3 stages. Also, the comparision between 3 aluminum alloy materials is carried out. The mechanical properties barely change up to a heat-treatment temperature of 300 °C. However, when the heat-treatment temperature exceeds 300 °C, the elastic modulus, yield strength, and ultimate strength sharply drop, and the percentage elongation after fracture significantly increases. At a heat-treatment temperature of 500 °C, the elastic modulus, yield strength, and ultimate strength respectively decrease to approximately 60%, 20%, and 45%, compared with those of the specimens without heat treatment, and the percentage elongation after fracture is approximately 1.9 times as high as that of the specimens without heat treatment. Predictive equations for the post-fire mechanical indices of post-high-temperature aluminum alloy 6082-T6 are established by fitting to the test data. The predicted results using the established equations are highly consistent with the experimental data; thus, the equations can provide key data for residual mechanical property evaluation of aluminum alloy structures after a fire.