Hiroyuki Higuchi, Makoto Sugamata and Junichi Kaneko
Department of Mechanical Engineering, College of Industrial Technology, Nihon University, Chiba
With a purpose of attesting selective oxidation of solute Li and Mg in solid Al, mechanical alloying was carried out for Al-Li and Al-Li-Mg alloys with or without addition of various metal oxides, and subsequently P/M materials were prepared. Constituent phases were determined by XRD for the mechanically alloyed powders and the as-extruded and heat-treated P/M materials. Hardnesses and microstructures were examined for the P/M materials.
It has been confirmed that Li is selectively oxidized and LiAlO2 is generally formed in the Al-Li alloys. In the Al-Li-Mg alloys, Mg is oxidized in preference to Li. After hot extrusion, hardness increases were not observed with progressing preferential oxidation and reduction of the added metal oxide. Coarsening of LiAlO2 particles was observed in the P/M materials after heating at 873 K. As-extruded P/M materials showed relatively high hardness and hence dispersion hardened materials of high mechanical strength can be expected by applying preferential oxidation of the solute in aluminum.
(Received June 3, 1996)
mechanical alloying, reaction milling, internal oxidation, powder metallurgy, aluminum-lithium alloy, aluminum-lithium-magnesium alloy, dispersion strengthened material
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