Characterization of protective layers produced by laser treatment

Metal matrix composite coatings prepared by laser melt injection (LMI) and thick metallic coatings (Iron, Nickel and Cobalt based) prepared by laser cladding were studied with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), orientation imaging microscopy (OIM) based on electron back scattered diffraction (EBSD) and by a combination of focused ion beam (FIB) and digital image correlation (DIC) of SEM images. Detailed information concerning the grain size and grain orientation together with texture characterization inside the coating will be presented. A possibility to determine phase characterization and orientation relationships between different phases by EBSD will be also demonstrated. Finally, an evaluation of internal stress on micro level inside the coatings and heat affected zones by a combination of focused ion beam and digital image correlation methods will be reported. Relationships between these microstructural characteristics and properties of the coatings will be shown and discussed in depth.