High-temperature mechanical properties of constructional 6082-T6 aluminum alloy extrusion

Abstract

The application of constructional aluminum alloys is snowballing owing to their high strength-to-density ratio, easy workability, corrosion resistance (high recycling), and good metallic texture. A macro-level understanding of material properties is not sufficiently comprehensive and quantitative to address all fire safety issues, particularly the effect of post high-temperature and creep. In this study, a systematic experimental investigation was conducted on 6082-T6 aluminum alloy extrusion at high temperatures, post high temperatures, and creep (ambient stress ratio: 0.944–0.026). The results showed that the material exhibits no safety reserve at high temperatures over 200 °C; further, at post high temperatures, the strength of the material is reduced at approximately 200 °C after a short-time thermal exposure. The rupture critical stress ratio αcr-Zone corresponding to a creep rupture time of 4.0 h decreases in an anti-S shape with an increase in temperature. Moreover, the strength of the material after exposure to a temperature of 350 °C for 1.0 h was nearly zero; therefore, 160 °C was suggested as the starting temperature of the thermal exposure effect. Additionally, more attention should be paid to the influence of the deteriorating role of creep on the overall structural fire-resistant bearing capacity under long-duration fires. Finally, a new-form reduction factor model of key mechanical property indexes, a two-stage constitutive model using the fast simulated annealing method, and a strain rate prediction model of Creep Stage II were proposed.