Most aluminum alloys in commercial use today were developed primarily based upon the elemental alloying additions needed to achieve the target performance requirements, including such properties as strength, toughness, and/or corrosion resistance.  It was taken for granted that whatever base metal requirements were needed would come from primary aluminum, to which the needed alloying elements were added.  Little or no consideration was given to the recycling process: what will happen when a product made of the alloy reaches the end of its life, and becomes available for recycling.  Today, for the first time, this approach is being replaced by one in which consideration of recycling characteristics are considered in alloy design; recyclability along with performance requirements are considered in designing new alloy compositions. 

This paper introduces a new approach by recognizing the relative recycle-friendliness of existing aerospace aluminum alloys, indicating which can be most easily recycled for direct reuse and which will require substantial reprocessing. The need for the recycling index is described, the basis of the Alloy Recycling Index documented, and some of the early conclusions that may be drawn from such an approach are laid out.