| 研究実績の概要 |
The need of advanced aluminum alloys with drastically higher specific strength emerged powerfully. However, a serious limitation of aluminum is that it is too soft. The scope is to study the microstructure and properties of the super-strong aluminum alloys with acceptable ductility. In this work, a super-high strength Al-Gd-Ni-Co alloy was produced and the wear and corrosion properties have been studied. Firstly, the results reveal that the nanostructure Al-Gd-Ni-Co alloy shows different corrosion behavior compared to the pure aluminum, because of the presence of high volume fraction of Al-based intermetallic compounds. The main corrosion mechanisms observed in the Al-Gd-Ni-Co alloy are found to be the pitting corrosion (corrosion of aluminum in the consolidated particles) and crevice corrosion (corrosion of aluminum in the inter-particle area). Secondly, for the high-strength aluminum alloys, the inter-particle regions, including soft aluminum and pores, are relatively weak compared to the consolidated particles. We have found plastic deformation, crack branching and deflection are observed in the inter-particle regions, giving rise to the arrest of cracks. The fracture mode of the Al-Gd-Ni-Co nanostructured alloy changes from the inter-particle failure to trans-particle failure with decreasing volume fraction of the inter-particle regions.
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