Experimental investigations on the ductility improvement due to stress relaxation in aluminium alloy 5083 under biaxial loading conditions

Abstract

The influence of stress relaxation on ductility improvement has been extensively studied for metallic materials, primarily through interrupted uniaxial tensile tests. However, components in typical press forming processes are subjected to multiaxial states of stresses. The applied load paths are expected to have a bearing on the failure strain post relaxation, which is infeasible to study under uniaxial loading. Therefore, single relaxation tests are carried out through interrupted planar biaxial tensile tests in cruciform samples of an aluminum alloy. The tests are performed at different load ratios to assess the load path dependency of stress relaxation, which is otherwise neglected.