Standard Test Methods of Tension Testing of Metallic Foil

Abstract

4.1 Tension tests provide information on the strength and ductility of materials under uniaxial tensile stresses. This information may be useful in comparisons of materials, alloy development, quality control, and design. 4.2 The results of tension tests from selected portions of a part or material may not totally represent the strength and ductility of the entire end product of its in-service behavior in different environments. 4.3 These test methods are considered satisfactory for acceptance testing of commercial shipments, since the methods have been used extensively for these purposes. 4.4 Tension tests provide a means to determine the ductility of materials through the measurement of elongation or reduction of area. However, as specimen thickness is reduced, tension tests may become less useful for determining ductility. For these purposes Test Method E796 is an alternative procedure for measuring ductility. 4.5 Different industries differentiate between foil and sheet at different thicknesses. Note 1: In 2013, to harmonize with international standards, the Aluminum Association revised its definition of foil to include thicknesses less than or equal to 0.2 mm (0.008 in.). 4.6 This standard differs from Test Methods E8/E8M in that it permits determining the specimen thickness by weighing (7.3) and determining the elongation from crosshead displacement for some specimens (7.8). 4.7 It is impossible for this standard to define the thickness range for every possible alloy where this standard should be used instead of Test Methods E8/E8M or other tensile test standards. Superior results for a specific alloy and thickness could be obtained by measuring the specimen thickness by weighing (7.3) to avoid damaging the material and to obtain sufficient accuracy. In addition, it may be acceptable for a given alloy and thickness to determine the elongation from crosshead displacement in cases where conventional extensometers that contact the specimen or scribed gauge marks could damage the specimen or affect the test results.