Work

Probing the high-temperature interfacial state during liquid-phase sintering of VC-doped WC–Co alloys via impinged (V,W)Cx grains

Year: 2026

Type: article

Abstract: Vanadium carbide (VC) doping controls tungsten carbide (WC) grain growth effectively during the liquid-phase sintering of WC–Co cemented carbides. While this inhibitory effect is typically attributed to a (V,W)C x layer at the WC/binder interface, the layer's thickness heavily depends on post-sintering cooling, obscuring VC's true high-temperature mechanism. To bypass these cooling artifacts, we investigated the impingement interfaces between pre-faceted WC grains and sub-micrometer (V,W)C x grains. Protected from the precipitation from Co-based liquid during post-sintering cooling, these boundaries act as snapshots preserving the WC surface state during high-temperature liquid-phase sintering. High-resolution scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed fully developed step-like microfacets at these interfaces. Crucially, the multi-atomic (V,W)C x layer conventionally observed at room-temperature WC/binder interfaces was absent on the WC (0001) habit planes. Atomic column intensity profiles and elemental analyses demonstrated that V segregated exclusively to the first atomic layer, while Co segregated to the second layer due to solute partitioning ahead of the advancing (V,W)C x growth front. Consequently, the complexion in this alloy is two-dimensional, exhibiting a thickness of approximately a single atomic layer. These findings suggest that the multi-atomic (V,W)C x layers observed at room temperature incorporate cooling artifacts resulting from precipitation from Co-liquid during post-sintering cooling. Therefore, it is reasonable to conclude that the VC inhibitory effect functions through a dynamic “poisoning mechanism” for WC grain growth suppression.

Source: International Journal of Refractory Metals and Hard Materials

DOI: 10.1016/j.ijrmhm.2026.108052

Authors: Kimitaka Higuchi, Ayu Kodaira, Masaru Kawakami, Sota Terasaka, Takahisa Yamamoto

Institutions: Nagoya University, Tohoku University, Japan Fine Ceramics Center

Language: English

Topic: Advanced materials and composites

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,310

Funders: Ministry of Education, Culture, Sports, Science and Technology, Japan Science and Technology Agency, Core Research for Evolutional Science and Technology