Effect of Sc and Heat Treatment on Microstructure and Properties of a 7XXX DC Cast Alloy

摘要

Four developmental 7XXX series alloys modified with Sc, Zr and other dispersoid-forming elements were produced by continuous direct chill (DC) casting. Microstructure and mechanical properties were evaluated in both the longitudinal and transverse directions at room and cryogenic temperatures. The homogenization, solution treatment and aging schedules were optimized to obtain superior mechanical properties. In particular, the Sccontaining cast alloys showed tensile properties similar or even superior to the properties of a wrought 7075-T6 alloy. The strengthening mechanisms responsible for this improvement, optimal Sc content and the processing parameters are discussed.