The effect of temperature of magnetic pulsed compaction on the characteristics of nanostructured aluminum compacts

Magnetic pulse compaction (MPC) allows one to maintain a nanostructured state in nano powder metallic compacts and to achieve near theoretical density. In this study, nano Al powders of about 80 nm in diameter were prepared with the Pulse Wire Evaporation (PWE) method and passivated with a thin Al₂O₃ layer on a surface about 2 nm thick to prevent further agglomeration and oxidation. The powders were compacted with the dynamic compaction of magnetic pulsed force. The effects of the compaction temperature and passivated oxide layer of Al powders on mechanical properties were investigated. The prepared compacts were considered as the composite materials of the metal-matrix containing oxides of their own metal. A fine and uniform bulk structure was kept up to 400°C, which showed neither further agglomeration nor grain growth during compaction and heat treatment due to the formation of Al/Al₂O₃ composites. This article is based on a presentation made in the 2002 Korea-US symposium on the “Phase Transformations of Nano-Materials”, organized as a special program of the 2002 Annual Meeting of the Korean Institute of Metals and Materials, held at Yonsei University, Seoul, Korea on October 25–26, 2002.