Laser treatment of A286 superalloy: corrosion resistance of the treated surface.

Laser controlled melting of metal surface provides a local treatment with improved surface properties such as corrosion resistance. In the present study, laser surface treatment of iron base superalloy (A286) is carried out. The corrosion resistance of the laser-treated surface is examined through potentiodynamic tests using 0.5 N NaCl solution. The microstructural and morphological changes in the laser-treated layer are investigated incorporating scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy. The residual stress formed at the laser-treated surface is measured using the XRD technique. It is found that laser treatment enhances corrosion resistance of A286 superalloy surface, which is attributed to the formation of fine grains and dense layer at the treated surface. Although locally scattered few corrosion induced microcracks are observed at the treated surface, they are not extended to form large cracks or crack network at the surface. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]