Abstract
AlCuLi based alloys are attractive for the aerospace and automotive industries for their relatively high strength and low density. Sheet applications suffer from anisotropy of mechanical properties necessitated by a high number of rolling steps during production from large scale DC cast ingots.
Formability and properties of these alloys could be improved by employment of alternative casting methods such as twin-roll casting (TRC), which produces thin sheets in the as-cast state combining casting and forming in a single step. The high cooling rates achieved during TRC cause a formation of a finer grain and cell structures with finer constituent particles.
In this study, two dilute AlCuLi alloys based on the AA2195 alloy composition, one with an addition of Sc, were investigated. A novel processing scheme is proposed, combining homogenization and solution treatment into a single step.
Dissolution of a large fraction of present constituent particles was achieved through this treatment due to shorter times of dissolution and transformation of small constituent particles and shorter diffusion lengths for solute redistribution in the TRC material. Heat treated materials were then aged for up to 100 h in oil.
Mechanical properties and microstructure of the materials at different stages of processing were studied using a combination of microscopic observations, hardness measurements and deformation testing.