Surface segregation of chromium in rapidly solidified al studied by rbs and spem

Depth profiling of elemental composition has been examined for rapidly solidified Al-Cr alloy foils containing 1.0 and 3.0 at % Cr by means of Rutherford backscattering spectroscopy (RBS) and scanning photoelectron microscopy (SPEM) using synchrotron radiation. Surface microstructure was monitored using atomic force microscopy (AFM). Analysis of SPEM images and X-ray photoelectron spectroscopy (XPS) spectra from the alloy constituents revealed Cr segregation beneath the foils surface with a corresponding depletion of the outermost surface layer. The deficiency of Cr at the near-surface region found here is in agreement with concentration depth profiles measured by RBS. The investigated segregation behaviour of alloying elements in Al-based foils is discussed concerning the role of lattice defects on solute/microstructure interactions toward hydrogen behaviour in RS materials