THE EFFECTS OF LASER SURFACE PROCESSING ON THE THERMALLY GROWN OXIDE SCALE FORMED ON AN NI-CR-AL-Y COMPOSITION

The effect of laser surface processing on the subsequent oxidation behavior of an Ni-Cr-Al-Y composition has been examined. Testing has involved both isothermal and cyclic testing of annealed and laser-surface-processed Ni-Cr-Al-Y surfaces in air to a temperature of 1050 degree C. For the oxidation of the alloy in the as-annealed state, adherent and protective oxide scales with complex morphologies were produced. Dependent on both the alloy surface state (annealed or laser processed) and the test conditions, the yttrium distributions within the scales differed markedly. No oxide 'pegs' were detected in oxide scales growing on laser-processed surfaces. Initially present oxide scales formed during the laser processing operation were not responsible for the effects observed here.