Finite element simulation of a new deformation type occurring in changing-channel extrusion

There has been a number of investigations in recent years reporting the results obtained on the structure and properties of metals deformed to large strain. Being deformed to large strain, ultra-fine grains (UFG) are usually formed, and materials with UFG structure display many abnormal characteristics, which have attracted a growing research interest. The method often used to obtain large strain is equal-cross-section lateral extrusion (ECSLE) or equal channel angular pressing (ECAP). However, according to the simulation results, there is large tensile stress in the workpiece during deformation, which may lead to cracking. In this paper, a new method, changing channel extrusion (CCE), is presented, which could decrease the tensile stress and increase the hydrostatic pressure in the workpiece, which is good for the plastic deformation of low ductility materials.