Mechanical properties of 6022 aluminum alloy sheets with high iron content fabricated by a high-speed twin-roll caster

Influence of iron content (0.2-1.0 mass %) and solidification rates (3-1200°C/s) during casting on mechanical properties of 6022 base aluminum alloys were investigated. Molten alloys were cast into about 3 mm thick plate by a vertical-type high-speed twin-roll caster (HSTRC). Conventional book-type mold casting with a thickness of 5 mm and 50 mm were also fabricated for a purpose of comparison. The castings were rolled into 1 mm-thick sheets and then heat-treated. Iron content had a small effect on tensile strength of the sheet for both T4 temper and after baking-treated conditions. While, elongation decreased with increasing iron content. Solidification rates also had a small effect on the strength, though HSTRC sheet exhibited a little higher strength. This is considered to be due to higher solute content in the Al matrix of the rapidly solidified HSTRC product. Bendability was also deteriorated with the increase of iron content. It was remarkable for the sheet produced from the 50 mm-thick plate with the low solidification rate. Improved bendability of the sheets fabricated from high solidification rate products (HSTRC and 5 mm-thick plate) was considered to be mainly due to the finer second phase particles.