Publications Details
Microstructures of cubic Al sub 2 O sub 3 precipitates in oxygen-implanted aluminum
The microstructure of Al ion-implanted at room temperature with 17 at. % 0 has been characterized with TEM. The alloy has extremely small (1.5--3.5 nm) oxide precipitates whose crystal structure is interpreted to be a disordered version of {gamma}-Al{sub 2}O{sub 3} having a fcc lattice of O{sup 2{minus}} ions with Al{sup 3+} ions in random interstitial sites. The small sizes can account for the exceptionally high strength of as-implanted alloys: 2500--3300 MPa. Larger precipitates are found when the alloy is annealed 1/2 hour at 550{degree}C, which is consistent with its somewhat lower strength: 800--1600 MPa. 4 figs.