Regulating heat input for additive manufacturing of oxide inclusions-free ODS-FeCrAl steel

Laser-based powder bed fusion (PBF-LB) of oxide dispersion strengthened (ODS)-FeCrAl steel commonly results in the generation of Y–Al–O oxide inclusions in the matrix. In this study, different heat inputs were obtained by adjusting the laser scanning speed, and systematic correlations were established between the heat input and both the molten pool geometry and oxide inclusions content. ODS-FeCrAl steel without Y–Al–O oxide inclusions was prepared when the heat input was 109 J/mm³, where the depth of molten pools was sufficient to remelt previously six deposited layers. The increased heat input of molten pools resulted in coarsening of both grains and nano-precipitates, and the yield strength of the oxide inclusions-free ODS-FeCrAl steel was reduced by 37 MPa. This study provides a feasible method for in-situ removal of oxide inclusions in alloys during the PBF-LB process.