Indian Journal of Science and Technology

Abstract

Background/Objectives: Pressed and sintered Al1100 powder is subjected to Equal Channel Angular Pressing (ECAP) process to study densification and deformation behaviour under different initial relative density and shear friction conditions. Methods/Statistical Analysis: Commercially pure Aluminium (Al 1100) powder containing 99% Al, 0.05–0.2% Cu, 0.05% Mn, remainder of Si, Fe and Zn is processed through normal powder metallurgy route followed by ECAP process. Finite Element Analysis through simulations are carried out using DEFORM 2D software for different initial relative densities of 0.700, 0.750 and 0.800 under three friction coefficients of 0.05, 0.075 and 0.15. Effective stresses, strains and loads are plotted. Findings: Full densification is achieved near the inner corner of the die channel compared to the outer corner at the end of the process. Uniform densification (relative almost greater than 0.980) is achieved in the middle portion of the specimen. As the friction is increased load required also increases. Formation of dead zone near the inner corner of the die channel reduces as the initial relative density is increased from 0.700 to 0.800. With higher initial relative density, complete densification occurs in the lower friction conditions like close to 0.05 shear friction coefficient. Effective stress is higher in the plane of intersection of the die channels where the actual deformation occurs. With the increase in initial relative density, effective strain also increases along the length of the specimen whose value is higher near the top portion of the die channel as compared to the bottom portion. Application/Improvements: ECAP eliminates residual porosity. Ultra fine grained structures are produced, even finer (better mechanical properties) than that by ECAP of cast products. Best suited for aerospace, defence and biomedical applications.
Keywords: Aluminium, Densification, ECAP, Powder Metallurgy, Simulation