Microstructural and mechanical properties of commercially pure aluminum subjected to Dual Equal Channel Lateral Extrusion

This paper aims to provide an introductory insight about Dual Equal Channel Lateral Extrusion, a counterpart of Equal Channel Angular Extrusion. The process is implemented to severely refine the microstructure of aluminum slabs. Comparisons of macroscopic parameters as average straining and large scale distribution of strain, as well as process loads reveal the supremacies and short comings of DECLE with respect to ECAE. DECLE shares a relatively similar geometry of deformation with that of ECAE. The advantages of this process with respect to ECAE are: (i) more intensive strains attainable per pass, and (ii) less extruding power needed for a given sample size. Nonetheless, less homogeneous strain per pass is seen in case of DECLE. TEM inspections revealed remarkable refinement of the microstructure through out the process and also some recrystallization at the final passes. Hardness tends to increase through successive passes to a limiting value beyond which there appeared a decline associated with intense recovery and the recrystallization observed. Compression tests exhibit the same trend, viz. a general rise in strength followed by a decrease in work hardening with increasing number of passes, leading to uniform microstructure and hardness after 9 passes. (C) 2009 Elsevier B.V. All rights reserved.