This research is aimed at fundamental questions regarding the oxidation behavior and structure of aluminum-lithium alloys. In the process of examining these alloys, new characterization techniques are developed in the use of Secondary Ion Mass Spectrometry (SIMS). Specific areas being addressed include: (1) oxidation behavior of aluminum-lithium alloys with emphasis on nucleation of the oxide, growth phenomena, and lithium depletion; (2) lithium diffusion and solute redistribution in the alloys; and (3) structural and chemical characterization of intermetallic phases in the alloys. This research is pertinent to further development of this important class of metal alloys, and the characterization techniques being developed are generic to all materials. The program is a collaborative research effort involving the Universities of Chicago and Lehigh and the National Institute of Standards.