Nano-second puise laser treatment of Incoloy 800 HT alloy-corrosion properties

Incoloy alloy 800 HT is widely used material of construction for equipment that must resist corrosion. Moreover, the corrosion properties of the alloy reduce considerably when the alloy is heat treated. However, the short pulse laser treatment of the alloy may offer alternative technique to improve the corrosion properties of the alloy, in the present study, nano-second pulse heating of Incoloy 800 HT alloy is carried out using a Nd-YAG laser. The heating rate and the temperature rise during the laser treatment are predicted theoretically. Electrochemical techniques are applied to determine the corrosion rates of the laser treated and untreated Incoloy 800 HT samples. SEM and EDS are introduced for metallographic examination of the treated alloy surface. It is found that the fine dentritic structures occur at the surface after the laser treatment. The local pitting is observed for the laser melted and re-solidified regions while the scattering of the pits are resulted for the laser heated and unmelted regions. In addition, the corrosion rate reduces for the laser-treated samples.