Microstructure and mechanical properties of medium entropy cemented carbides
Kunlong Cai, Jialin Sun, Zhennan Cao, Bin Li, Bo Liu, Chengqiang Fan
Abstract
This investigation is devoted to exploring medium entropy carbides (MECs) and medium entropy alloys (MEAs) as innovative alternatives to the WC hard phase and Co bonding phase in conventional cemented carbides. A series of new cemented carbides such as WC-10CoNiFe, WC-10CoNiCr, (NbTaW)C-10CoNiFe and (NbTaW)C-10CoNiCr have been successfully fabricated. The microstructures and mechanical properties of medium entropy alloy bonded cemented carbides (MEACCs) and medium entropy cemented carbides (MECCs) were investigated. The results indicate that MEACCs employing MEAs as the binder phase exhibit considerably enhanced fracture toughness and transverse rupture strength compared to conventional WC-10Co alloys. MECCs exhibit exceptional overall mechanical properties. The dominant toughening mechanisms were determined as crack bridging and crack deflection. The primary hardening mechanisms were determined as grain refinement, solid solution strengthening, and unique interfacial effects. The feasibility of MECs and MEAs as replacements for the WC and Co phases of cemented carbides has been demonstrated, and has greatly broadened the freedom in microstructural design and optimization of the mechanical properties of custom cemented carbides.