Investigation of the diffluence mechanism of an aluminium alloy ring under compression

Abstract

In order to study the mechanism of diffluence behaviour of an aluminium alloy ring under compression, the finite-element model simulations with different deformation conditions are carried out in this study. The plastic-forming mechanics are investigated based on the Lode parameter and the second invariant of the deviator stress J ₂. Based on the numerical results, the effect of deformation conditions on the diffluence behaviour of the aluminium alloy ring is evaluated. It is shown that with an increase in the height—diameter ratio and the flow of metal towards the internal hole decreases, the hard deform zones expand and the diffluence surface shifts towards the left; with an increase in the friction factor and internal pressure, the flow of metal towards the hole increases, the diffluence surface shifts towards the right, and the strain in the plastic area changes from single compression to three coexisting modes.