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 7178 is a wrought aluminum alloy containing zinc, magnesium and copper capable of heat treatment to yield strengths of typically 73-75 ksi.