Pressure required to initiate extrusion in some aluminium alloys

Abstract

The breakthrough pressure required to initiate extrusion has been defined, and experimental evidence shows that it is related to the pressure required for steady-state extrusion. This peak pressure is thermally activated, and the structural analysis presented indicates that it is associated with the dislocation density required to establish a quasi-static deformation zone. In this paper, the results of over 200 extrusion trials are reported and it is shown that the additional pressure required to initiate extrusion in some aluminium alloys may be as high as 20%.