Phase Evolution and Corrosion Performance of Laser Processed Oxide Dispersion Strengthened Ferritic Alloys

The application of laser processing as a surface treatment method on oxide dispersion strengthened (ODS) Fe-14Cr ferritic alloys, Fe-14Cr-3W-0.3Ti-xY₂O₃ (x = 0.3, 0.6, 0.9) (wt%), was examined in this paper. The ODS ferritic alloys with different amount of Y₂O₃ particles were prepared by mechanical milling and subsequently consolidated by spark plasma sintering (SPS). The effect of surface laser processing on the corrosion behavior was investigated for these ODS alloys with different oxide contents. The corrosion behaviors of SPS consolidated ODS samples with subsequent laser melting/solidification were examined by the means of electrochemical tests and compared with the untreated ODS samples in salt water. Results indicated that for samples without laser treatment, powders are mainly in their elemental state. However, after laser processing, the formation of passive layer and the improvement in the corrosion resistance are noticeable. CALculation of PHAse Diagrams (CALPHAD) calculations were used to identify the equilibrium phases and compared well with the experimental results.