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.UNISPAN 36 is a 36% nickel-iron alloy having low thermal expansion in a -400 F to +350 F range. It is recommended for parts in precision machinery and for applications where dimensional changes due to temperature variation must be minimized.