Equal Channel Angular Extrusion of AA 5083

Abstract

Equal Channel Angular Extrusion (ECAE) is used as a top down process to produce bulk nano/ultrafine grain structured materials by inducing high amount of strain with less experimental set up. In the present study AA 5083 alloy with circular and square cross sections are extruded at room temperature using two dies having cannels with circular and square cross sections respectively. Both the dies used in this study are having same channel angle (Φ)1200 and outer corner angle (Ψ) 200. The circular and square billets are extruded for four times in route BC. The objective of this work is to study the effect of cross section of the billet, number of passes on grain refinement, mechanical properties and wear behaviour of AA 5083. Significant reduction in grain size is observed in extruded material using Field Emission Scanning Electron Microscope (FE-SEM) in the range of 80nm to 600nm after four passes. The microhardness in extruded materials is improved with no. of passes in both cross sectioned billets and it is more predominant for square billets even after two passes. The effect of dead zone is less in case of square billets and hence they have shown more structural homogeneity. The dry sliding wear tests are conducted to study the wear behaviour of the ECAEd materials. It is observed that the wear rate and coefficient of friction are reduced with number of passes in both the cases and rate of decrease is more in case of square billets.