View Sample Alloy Digest Data Sheet (PDF)Since 1952, Alloy Digest has been the leading reference for materials property data on metals and alloys used throughout the world. Featuring graphs, charts and tables, these sheets give facts and figures on composition or characterization, physical and mechanical properties, heat treatment, and machinability.AA 2124 is a heat treatable aluminum plate alloy in which copper is the principal strengthening element. The alloy carries reduced allowable silicon and iron contents to ensure improved toughness.