Study on microstructure, mechanical properties, and texture of the CC AA 3105 aluminum alloy processed by high-pressure heat treatment

Abstract

The hot band of CC AA 3105 aluminum alloy sheets underwent 6 h of preheating treatment at 599 °C. Then, it was cold-rolled to various reductions, followed by 1 h of annealing at 482 °C under various pressures. The study investigated the alternation of microstructure, mechanical properties, and texture of these sheets. High-pressure heat treatment (HPHT) remarkably weakens the pinning effect and refines recrystallized grains. In the case of the annealed sheets of which the rolling reduction reached 91.3%, in the atmospheric pressure-to-6 GPa pressure increasing range, the fine precipitates (1–3 nm) disappeared. In contrast, there is an increase in large precipitates and a reduction in the average grain size. Furthermore, the aspect ratio elevated from 0.19 to 0.87, and the average grain size along the rolling direction (RD) reduced from 182.4 µm to 57.9 µm. Pressure elevation was accompanied by enhanced strengths of the P and r-cubeND textures but remarkably decreased strengths of the M texture. The elongation of the sheets decreased with increasing pressure. The ultimate tensile strength (UTS), yield strength (YS), and hardness decreased when the pressure rose from atmospheric pressure to 2 GPa and increased in the 2 GPa-to-6 GPa pressure increasing range.