Enhanced laser printability and strength-ductility synergy in oxide dispersion strengthened (ODS) GH3536 superalloy manufactured by laser powder-bed fusion

Additively manufactured oxide dispersion strengthened (ODS) Ni-based superalloy exhibits superior mechanical properties and exceptional oxidation resistance, demonstrating significant potential for applications in high-temperature environments. In this work, a series of ODS GH3536 superalloys with varying Al₂O₃ contents (0.8, 1.5, and 2.0 wt%) were prepared by laser powder-bed fusion (LPBF). Crack-free ODS samples were fabricated through process parameter optimization and appropriate Al₂O₃ addition. The suppression of microcracks is correlated with reduced residual stress and coarsened grain structure, indicating modified solidification conditions with lower cooling rates and thermal gradients. The decreased strain energy combined with dispersed Al₂O₃ particles inhibited recrystallization and suppressed grain growth, allowing the alloy to retain a fine-grained structure after heat treatment. In addition, the nano-Al₂O₃ particles significantly promoted carbide precipitation. Consequently, the combined effects of solid solution strengthening, grain boundary strengthening, precipitation strengthening, and dislocation strengthening enabled a strength-ductility balance in the heat-treated ODS alloy with 1.5 wt% nano-Al₂O₃ introduction. Specifically, the alloy achieved an ultimate tensile strength of 1072 ± 12 MPa (a 44% increase compared to pure GH3536) and an elongation of 44% ± 2% (a 7% improvement). These findings provide novel insights into crack suppression mechanisms and mechanical property enhancement in additively manufactured Ni-based superalloys.