Measurement and Analysis of the Strength Differential Effect of 5000 Series Aluminum Alloy Sheet

Tension-Compression Asymmetry (TCA) of a 1.5-mm-thick 5000-series aluminum alloy sheet, A5083-O, is measured using a uniaxial tensile test and in-plane compression test. In particular, the TCA observed for annealed materials is referred to as the Strength Differential Effect (SDE). The in-plane compressive flow stress is 2–6% higher than the uniaxial tensile flow stress; therefore, the material exhibits the SDE. Moreover, a stacked compression test in the thickness direction of the test sample is also performed to measure the hydrostatic stress dependency of the yield stress. The uniaxial compressive flow stress in the thickness direction is almost identical to the equibiaxial tensile flow stress measured using a cruciform equibiaxial tension test (ISO 16842) and a hydraulic bulge test; therefore, the hydrostatic stress dependency of the yield stress has not been confirmed. Hence, it is concluded that the SDE observed in the A5083-O is not caused by the hydrostatic stress dependency of the yield stress.