Abstract
Nanostructured metals, in which the grain sizes are in the range of 1 to 100 nm, have superior mechanical, unique physical and chemical properties. Nanostructured metals with bulk size have a wide range of engineering applications. Bulk nanostructured metals can be produced by severe plastic deformation. Among the various severe plastic deformation methods, equal channel angular pressing (ECAP) is the most promising one and therefore it has attracted increasing research attention in the last few years. As the grain refinement is directly related to the amount of plastic deformation, it is very important to understand the phenomenon associated with the strain development in ECAP. Finite element method (FEM) has been used by some researchers to study the deformation behavior, strain and stress in the workpiece, in order to get a better understanding of the ECAP process and to optimize the process conditions. However, in these studies the isothermal conditions were assumed, which is only correct for very low pressing speed. For high pressing speed, the deformation heating will result in very obvious temperature rise in the workpiece. The temperature rise will change the flow stress of the material, and thus influence the deformation behavior of the workpiece during ECAP. In addition, the temperature rise will change the recrystallization temperature, and thus affect the grain size formed. In this article, we present the coupled thermo-mechanical finite element analysis of ECAP to study the temperature rise and deformation behavior in the workpiece. We investigated the effects of pressing speed, pressing temperature, workpiece material and die geometry on the temperature rise and flow behavior during ECAP.