| dc.description.abstract | This study used microstructure observation, electrical conductivity (%IACS), electron backscatter diffraction (EBSD), electron microscope (SEM), nitric acid corrosion weight loss test, tensile test and hardness test (HRF), etc., to discuss the effects of Zr (0.15wt%)、Sc (0.1wt%), and annealing temperature on the recrystallization, corrosion and mechanical properties of Al-5Mg-0.7Mn alloy.
The results showed that the alloy containing minor of Zr (0.15wt%) and Sc (0.1wt%) will precipitate Al3Zr and Al3Sc dispersed phase particles in the grains during the homogenization process, which can increase the recrystallization temperature of the alloy and effectively. In addition, the addition of trace amounts of Zr and Sc can improve the strength of the alloy, and the strengthening effect of the alloy containing Sc is the most significant when the annealing temperature is 250 °C. When annealed at a low temperature (250 °C), the alloy is partially recrystallized, and most of it still has a textured microstructure. After sensitization treatment, the β(Mg2Al3) phase will precipitate discontinuously on the grain boundary and subgrain boundary. Therefore, the alloy has excellent resistance to sensitized corrosion. Because the recrystallization ratio of the alloy containing Zr and Sc is lower than that of the alloy containing Mn. The alloy containing Zr and Sc has better corrosion resistance.
When annealed at high temperature (≥300°C), the alloy is almost completely recrystallized, and the β phase will continuously precipitate on the grain boundary, resulting in a decrease in the alloy′s resistance to sensitized corrosion. The finer the grains, the lower the corrosion resistance. Therefore, the corrosion resistance of Mn-containing alloys is the best. The sensitized corrosion resistance of the alloy is slightly improved when grain growth is induced by annealing at a high temperaturessure. | en_US |