FCC TITANIUM IN TI-AL MULTILAYERS

Thin titanium films deposited on aluminum, in a multilayered form, wer e found to transform from a hexagonal close-packed (hcp, P63/MMC) stru cture to the face-centered cubic structure (fcc, FM3M) upon thinning o f cross sections for TEM study. The transformation results in twinned Al and Ti layers with noncoherent SIGMA = 3 boundaries separating the twin related crystals in each layer. The as-deposited Ti is hcp and th e Al fcc. The Ti layers studied varied in thickness between 30 and 500 nm. They were deposited by electron beam evaporation in vacuum, using 30 nm thick layers of Al to form multilayered films which contained b etween 10 and 100 bilayers. The study was conducted by TEM and X-ray d iffraction and the hcp to fcc transformation of the Ti layers was obse rved in all the multilayers.