On the strain distribution during extrusion through a bent channel

The concept of equal channel angular pressing (ECAP) as a method of imparting significant amount of work to materials without causing reduction in section size to produce fine grain structure was developed in early 1980s. Several modifications are being made to the theory to accommodate the observed deviations in behaviour of materials during processing. In all these analyses, it is assumed that the material moves at a constant speed across the whole cross-section. In this paper we examine the strain experienced by materials when they are extruded through a bent channel under the assumption that cross-sectional planes remain planar, as in elastic bending, which does not permit constant speed of movement of the material across the cross-section. Finite element analysis (FEA) of extrusion through bent channel led to discovery of a new mechanism by which shear is induced in the material apart from the expected tensile and compressive strains.