Metallurgical Abstracts on Light Metals and Alloys vol.55

Formation of Particle-Dispersed Nanocomposite and Supersaturated Solid Solution by Mechanical Alloying of Al and Al2O3 Powders

Tatsuaki Sakamoto*, Tomoharu Mizuka*, Shinya Shiga** and Hiromichi Takebe*
*Department of Materials Science and Biotechnology, Ehime University
**National Institute of Technology, Niihama College

[Published in Materials Transactions, Vol. 63 (2022), pp. 141–147]

https://doi.org/10.2320/matertrans.MT-L2021016
E-mail: sakamoto.tatsuaki.mm[at]ehime-u.ac.jp
Key Words: Metal matrix composites, Powder metallurgy, Mechanical alloying, Supersaturated solid solution, Precipitation

We investigated the mechanical alloying (MA) processes of Al and Al2O3 powders via X-ray diffraction analysis, transmission electron microscopy (TEM), and Vickers microhardness. The yield strengths and microstructures of consolidated compacts were evaluated using tensile tests and TEM, respectively. When the amount of oxygen in the MA atmosphere was higher than a certain threshold, Al2O3 particles of about 7 nm were precipitated in the Al grain interior from a supersaturated solid solution (SSS) of Al—O due to significant precipitation driving force. Two types of alloyed powders were obtained: Al2O3 particle-dispersed Al nanocomposite and SSS. The consolidated compact of the former exhibited smaller Al grains and higher yield strength than the latter due to the enhancement of the pinning effect on Al grain boundary migration during consolidation. The difference in the nature of the two kinds of powders affected the Al grain sizes and yield strengths of the consolidated compacts.

Variation of lattice parameters as a function of milling time for the specimens fabricated via intermittent MA and continuous MA.