Experimental and finite element studies of the divergent extrusion process under conditions applicable to cold pressure welding of commercial purity aluminium

In the present investigation the divergent extrusion method, originally designed for simulation of cold pressure welding, has been further developed and explored. As a starting point the combination of advanced process instrumentation and finite element (FE) modelling is used to unravel the underlying material flow and deformation pattern during cold extrusion of commercial purity aluminium. It is shown that the plastic work within the shear deformation zone of the workpiece constitutes about 60% of the total forming load, the remaining being the result of friction, upsetting and plane strain compression. Because of this shear deformation the divergent extrusion process bears a close resemblance to equal channel angular pressing (ECAP).