Bauschinger Effect Investigation of an Aluminum Alloy, and Its Application in Autofrettaged and Compound Tubes

For characterizing Bauschinger effect factor (BEF) and Bauschinger modulus reduction of an A5083 aluminum alloy experimentally, several uniaxial tension-compression tests carried out in different pre-strain levels using INSTRON testing machine. BEF was investigated using both Welter and Milligan’s definitions for various offset values. It was observed that Milligan’s definition predicts BEF less than Welter’s definition for all offset values. In addition, real loading-unloading behavior of such alloy was recorded to predict residual stresses resulting from autofrettage and shrink fit processes. Variable material properties (VMP) method, which is capable of incorporating real unloading behavior of materials, was used as an accurate way to estimate residual stresses. Hoop residual stresses were calculated using real unloading behavior and isotropic hardening rule. Results showed that, isotropic hardening rule in comparison with real unloading behavior overestimates bore hoop residual stresses up to 12%.