Energy-loss near-edge fine structure and compositional profiles of cryomilled oxide-dispersion-strengthened aluminum.
Spatially resolved electron energy-loss spectroscopy (SREELS) makes possible the identification of small second-phase particles in an oxide-dispersion-strengthened aluminum alloy produced by mechanical alloying in a liquid-nitrogen slurry. Near-edge fine structure profiles based on aluminum L23 features that are characteristic of Al-Al or Al-O bonding yield the metal/oxide fraction as a function of probe position. Profiles of nitrogen fraction are derived from linear sequences of spectra so that detection limits can be analyzed at each point in a scan. Quantitative analysis of these linear profiles shows that particles with diameters in the range 10 to 30 nm are rich in nitrogen. A combination of statistical analysis of background removal results with visual inspection of derivative spectra is used to estimate detection limits.