Comparison of microstructure and mechanical properties of ODS nickel-based alloy fabricated by laser powder bed fusion and spark plasma sintering

This study investigates the microstructure and mechanical properties of modified oxide dispersion strengthened (ODS) nickel-based alloys fabricated using two advanced techniques: spark plasma sintering (SPS) and laser powder bed fusion (L-PBF). Gas-atomised powders with varying particle sizes (ODS-I and ODS-II) were used as the starting material to examine the influence of fabrication methods and powder characteristics on material performance. The SPS-fabricated samples achieved higher relative densities (up to 98.57%) and superior hardness (469 HV) due to the suppression of grain growth and the presence of secondary phases enriched in W­–Ti–Ta–Mo–Zr. Conversely, L-PBF samples demonstrated columnar grain structures and a more homogeneous distribution of alloying elements but exhibited lower hardness (up to 427 HV) due to residual stress and porosity from rapid solidification.