Microstructural Characteristics and High-Temperature Compression Behavior of a Ni-Based ODS-Composition Alloy and Refractory Composite

Nickel-based alloys have been widely used as high-temperature structural materials owing to their excellent oxidation resistance, phase stability, and mechanical reliability. However, their mechanical properties can rapidly deteriorate under ultrahigh-temperature conditions due to thermally activated dislocation motion, dynamic recovery, and grain-boundary-mediated deformation. Therefore, introducing thermally stable refractory constituents that retain high strength at elevated temperatures may provide an effective strategy for overcoming this limitation. In this study, Nb-Si-Ti-based refractory silicide alloy powder and Mo-based refractory alloy powder were introduced as reinforcing constituents to improve the ultrahigh-temperature deformation resistance of a Ni-based ODS-composition alloy. A Ni-MRC composite was fabricated by spark plasma sintering. The composite powder consisted of 65 wt.% Ni-based ODS-composition alloy powder, 25 wt.% Nb-Si-Ti-based refractory silicide alloy powder, and 10 wt.% Mo-based refractory alloy powder. Powder morphology, phase constitution, SPS-consolidated microstructure and ultrahigh-temperature compression behavior at 1050 °C were analyzed using SEM, XRD, EBSD, and Gleeble-based compression testing to evaluate the role of refractory reinforcements in improving the deformation resistance of the Ni-based matrix. The Ni-MRC composite exhibited a peak stress of 221 MPa at 1050 ℃, approximately 106% higher than that of the Ni-based ODS-composition alloy, indicating improved ultrahigh-temperature deformation resistance.