液体急冷したAl-Cu合金固溶体の相分解組織

抄録

Ribbon-shaped thin samples of Al-Cu alloys (4-33 mass%Cu) were obtained by the rapid solidification using a rotating single roller technique, and the decomposition structures were investigated with a high resolution electron microscope.
In the electron transparent regions, homogeneously supersaturated solid solution was found to be formed in Al-4-15 mass%Cu alloys, on the other hand, the combination of lamellar and cellular structures, and banded and randomly distributed structure of θ′ and θ phases were formed in addition to solid solution in Al-20-33 mass%Cu alloys.
It was also clarified that the characteristic fine periodic structure, in which the Cu concentration changed periodically in the ⟨100⟩ direction with the spacing of about 0.8 nm, was formed over a wide region in Al-20-33 mass%Cu alloys. The fine periodic structure, which is quite different from that of the well-known phase in the Al-Cu system, is considered to be a new metastable phase.