Influence of solute atoms on thermal stability of fibrous structure in 2024 aluminum alloy extrusion

Abstract

Influences of cooling rates after homogenization heat treatment and heating temperatures of ingots before extrusion on thermal stability of fibrous structure of 2024 aluminum alloy extrusion after T4 temper was investigated. The thermal stability of the fibrous structure was influenced by both the main elements (copper and magnesium) and the transition element (manganese). The fibrous structure was stabilized when the solute atoms of copper, magnesium and manganese were increased by rapid cooling after the homogenization heat treatment and the extrusion temperature was close to the nose temperature of the manganese precipitation. Therefore, the thermal stability of the fibrous structure decreased when the copper and magnesium were not present or the manganese amount was reduced by half. Furthermore, the cooling rate and the heating temperature influenced the crystallographic texture of the extrusion. When the fibrous structure was stable, cube and brass texture tended to increase, while the copper texture tended to decrease in the F temper. The formation of the crystallographic texture was affected by recovery with precipitation of copper and magnesium during the extrusion process.