Influence of Crystallite Size on Consolidation of Carbon Nanotube Reinforced AA 4032 Composite Powders by Equal Channel Angular Pressing
Equal channel angular pressing (ECAP) is the one of the promising methods of severe plastic deformation to obtain bulk ultrafine grain structures. However, ECAP can also be used for powder consolidation. In the present study, fully dense bulk AA 4032 alloy was consolidated from nanocrystalline and microcrystalline powders. These materials were processed by ECAP until four passes at ambient temperature. It is observed that hardness and densification increased significantly with increase in number of ECAP passes. Transmission electron microscopic and scanning electron microscopic examinations evidenced that crystallite size of the nanopowders are unaltered, however a significant crystallite size reduction from around 50 µm down to submicron size is observed. Moreover, higher densification is achieved in microcrystalline powders than nano powders, whereas higher hardness in the case of nanopowders compared to microcrystalline powders.
S.M. Sapuan, F. Mustapha, D.L. Majid, Z. Leman, A.H.M. Ariff, M.K.A. Ariffin, M.Y.M. Zuhri, M.R. Ishak and J. Sahari
M.S. S. Saravanan et al., "Influence of Crystallite Size on Consolidation of Carbon Nanotube Reinforced AA 4032 Composite Powders by Equal Channel Angular Pressing", Key Engineering Materials, Vols. 471-472, pp. 127-132, 2011