P. N. Comley, The Boeing Company, Seattle, WA; R. Davies, Battelle Pacific Northwest National Laboratory, Richland, WA

Summary:

Recently a method to define the Superplastic properties of a material has been proposed to ASTM for consideration for a new standard. This paper outlines the main points of the proposal. It defines the shape of the coupon to minimize errors of measurement, the use of constant strain rate to pull the test specimen , the generation of true stress and true strain data, and the format in which that data should be presented. The generation of strain rate sensitivity (‘m’) and strain hardening (‘n’) values are also discussed. A suggestion to use the data in tabulated form for finite element analysis (FEA) computer modeling is discussed.