Effect of hot rolling finishing temperature and intermediate annealing on the microstructure, texture evolution, and comprehensive properties of Al-Mg-Si alloy

Abstract

The effect of varying hot rolling finishing temperature and the application of intermediate annealing on the microstructure, texture evolution, and mechanical properties—including forming, hemming, and roping properties—of Al-Mg-Si alloy sheets was systematically investigated. The hot-rolled plate with a higher rolling finishing temperature exhibits a significantly higher volume fraction of Cube texture which is readily retained and inherited to the final state microstructure. A substantial quantity of Mg2Si particles can also be observed in this plate, while the amount notably decreases at lower rolling finishing temperatures. These large quantities of Mg2Si hinder the PSN effect, subsequently encouraging Cube texture and hindering CubeND texture formation during solute solution. Following intermediate annealing, Ostwald ripening mechanism leads to finer Mg2Si particles dissolve while the coarser Mg2Si continue to grow, reducing the obstruction to the PSN effect. The T4P sheets without intermediate annealing exhibit a significant volume fraction of Goss texture. Goss texture can be effectively minimized by applying intermediate annealing process and thus almost disappears in T4P sheets that undergo intermediate annealing. Cube texture proved advantageous for hemming processes but detrimental to both formability and roping performance; thus, it should be modulated within an optimal range. On the other hand, Goss texture negatively impacted all mechanical properties and should be minimized or eliminated. Optimal comprehensive properties can be achieved by lowering the hot rolling finishing temperature and implementing a suitable intermediate annealing treatment.