Design of novel sustainable cemented carbides strengthened by η-phase to replace critical raw materials

Cemented carbide production is heavily reliant on critical raw materials (CRMs) such as tungsten (W), cobalt (Co), titanium (Ti), tantalum (Ta), niobium (Nb), and ruthenium (Ru), which face increasing supply risks, cost volatility, and environmental challenges. This study presents a sustainable alternative through the design of WC-based cemented carbides reinforced with finely dispersed η-phase carbides. The η-phase morphology and distribution are tailored to substitute conventional γ-phase formers (Ti, Ta, Nb), allowing the replacement of Co binder metal, and minimizing reliance on scarce elements such as Ru. The resulting microstructures exhibit enhanced high-temperature strength, hot hardness, and fracture resistance. Cutting performance tests under severe thermomechanical loading conditions confirm that the new η-phase–reinforced grades offer equivalent or superior performance compared to conventional grades. A detailed Product Carbon Footprint (PCF) analysis demonstrates significantly lower environmental impact and material criticality, establishing η-phase strengthening as a robust strategy for developing next-generation, high-performance cemented carbides with improved sustainability.