SiC Particles Boost Wear Resistance of SPS-Sintered FGH95 Superalloy Composites

Engineers at the Institute of Materials Science, Vietnam Academy of Science and Technology, together with a colleague from Hanoi University of Industry, have reported a laboratory route to tougher nickel-based superalloy composites. By mixing 2.5 to 10 volume percent silicon carbide particles into FGH95 superalloy powder using high-energy ball milling and then consolidating the mixture with spark plasma sintering, the team produced dense compacts whose sliding wear rate fell from about 5.2 × 10⁻⁴ to 2.9 × 10⁻⁴ mm³ N⁻¹ m⁻¹ as SiC content rose to 10 volume percent, an improvement of roughly 45 percent.

FGH95 is a nickel-based superalloy with a two-phase γ/γ′ microstructure. The composites were examined for how the added ceramic particles affected that microstructure, the crystallographic relationship between the two matrix phases, and the resulting mechanical and tribological behavior. All specimens reached relative densities above 98 percent, indicating near-full densification after sintering.

X-ray diffraction analysis confirmed that the γ/γ′ matrix phases and the SiC were retained after spark plasma sintering, with no detectable reaction products between the ceramic particles and the alloy.

The diffraction data also tracked how the lattice parameters of the two matrix phases shifted with SiC content. The calculated γ/γ′ lattice misfit decreased continuously from 0.745 percent for monolithic FGH95 to 0.567 percent for the composite containing 10 volume percent SiC, although the individual γ and γ′ lattice parameters showed a slight non-monotonic variation at the highest SiC content. The authors associate the improved wear resistance in part with this improved γ/γ′ crystallographic compatibility.

Grain refinement was modest. Etched SEM observations and statistical grain-size analysis showed the average grain size decreasing only slightly, from 1.15 ± 1.2 μm for monolithic FGH95 to 1.01 ± 1.0 μm for the 10 volume percent SiC composite, with substantial overlap among the grain-size distributions. The SiC particles therefore did not dramatically restructure the matrix; their main effect appears to lie elsewhere.

That effect showed up clearly in hardness. Vickers hardness increased from approximately 470 to 575 HV as SiC content rose across the studied range. The uniformly dispersed ceramic particles provide a load-bearing capability during contact, and the authors attribute the enhanced wear resistance primarily to this increased hardness together with the high densification of the sintered compacts.

The worn surfaces told a consistent story. Monolithic FGH95 displayed severe abrasive–delamination wear. In the SiC-reinforced composites, the dominant mechanism shifted to predominantly mild abrasive wear, a less damaging material-removal mode under the sliding conditions tested.

The study is a laboratory investigation of sintered compacts over a specific SiC range, so the reported wear-rate reductions and hardness gains apply to the conditions and compositions examined. The work was received on 30 July 2026 and accepted on 12 October 2026, and the final formatted version is pending publication in Frontiers in Materials.

Within that scope, the findings suggest that simply dispersing silicon carbide particles into FGH95 powder before spark plasma sintering can deliver a meaningful tribological benefit without disrupting the alloy’s characteristic γ/γ′ microstructure or triggering interfacial reactions, offering a straightforward processing strategy for wear-resistant superalloy composites.

Subject of Research: Fabrication and tribological performance of SiC-reinforced FGH95 nickel-based superalloy composites made by spark plasma sintering

Article Title: Microstructural evolution and tribological performance of SiC-reinforced FGH95 superalloy composites fabricated by spark plasma sintering

Article References: Van Trinh, P., An, N. B., Van Hau, T., Trinh, N. D., Trung, T. B., & Phuong, D. D. (2026). Microstructural evolution and tribological performance of SiC-reinforced FGH95 superalloy composites fabricated by spark plasma sintering. Frontiers in Materials, 13, Article 1953344. https://doi.org/10.3389/fmats.2026.1953344

Image Credits: AI Generated

DOI: 10.3389/fmats.2026.1953344

Keywords: FGH95, nickel-based superalloy, silicon carbide, spark plasma sintering, hardness, wear resistance, lattice misfit, composites, microstructure, tribology, Microstructural, evolution