Functionally graded cemented carbides elaboration by imbibition process—Better understanding of liquid migration and homogenization mechanisms for an improved process
Résumé
Cemented carbides are used in rock drilling, for mining tools and other wear-resistant parts. These composite materials possess an excellent compromise between hardness and toughness. Currently, the concept of graded structure (FGM) is widely studied to improve these two properties simultaneously, and thus to increase the service life of drilling tools. This paper focuses on the imbibition process. The imbibition process gradually enriches the core of dense cemented carbide with binder phase and is based on the principle of liquid-phase migration in a solid/liquid body. FGM generated by such techniques shows interesting mechanical properties gradient, such as 400 HV on 20 mm hardness gradient. Hardness gradient development is achieved through a better understanding of kinetics and other phenomena occurring during imbibition. The goal is to select suitable process parameter for each grade of carbide.