The ASTM International Standard Test Method for Determining the Superplastic Properties of Metallic Materials
Over the last 40 years there have been many papers published showing superplastic properties of metallic materials. However there has been no standardized test available to assess and compare material, and researchers and companies in the field have devised a number of different methods to show superplastic properties. The value of these properties can vary dependent on the test method used. ASTM International (formerly The American Society for Testing and Materials ) has developed a standardized test method for superplastic properties. The standard is intended for all to use as a common platform for testing, evaluating and publishing superplastic properties to a uniform format, useful for both academia and industry. The paper outlines the main points of the standard, including:- The coupon geometry and the method of clamping the coupon in the grips. The furnace and test machine requirements. The testing conditions and the method of pulling the coupon. The analysis of the load and extension data from the test, and the standard presentation of superplastic properties. The basic superplastic properties of stress versus strain for any particular constant strain rate. The method to determine ‘m’, using a step method at a particular strain. Some data is presented showing how the properties of fine grain Ti-6Al-4V titanium alloy are derived and presented using the standard.
P. N. Comley "The ASTM International Standard Test Method for Determining the Superplastic Properties of Metallic Materials", Materials Science Forum, Vols. 551-552, pp. 105-110, 2007