Investigation on pressureless cosintering behaviour of Hadfield steel/cemented carbide bimaterials

Abstract

This study aims at understanding the physicochemical phenomena which take place during pressureless cosintering of Hadfield steel (X120Mn12) and cemented carbide (WC cemented by an Fe rich binder). The experimental approach consists in studying the sintering behaviour of single materials (dimensional changes and weight losses during sintering, microstructure and hardness after sintering) before studying cosintering. Two bimaterial architectures are investigated: one consists of a two layer bimaterial and the other consists of cemented carbide inclusions in steel matrix. For both architectures, when the contact between materials is achieved, a multiphase intermediate layer appears between the two materials. This intermediate layer consists of a M₆C continuous matrix with remaining WC grains at the cemented carbide side and with Fe rich islands at the steel side. M₆C formation is the result of WC dissolution and asymmetric diffusion of W and C in the steel layer.

Keywords:

• Bimaterial component
• Hadfield steel
• Cemented carbide
• Cosintering
• Densification
• Interface microstructure

The authors wish to express their thanks to Eurotungstene Poudres (Grenoble) for raw materials. The authors acknowledge Direction Générale des Entreprises, Conseil Général de la Loire and Saint Etienne Métropole for their financial support of the ‘MULTIMAT’ Project, within the Competitiveness Cluster ViaMéca and CETIM Foundation for its financial support of the ‘Multimaterial and Multifunctional Products’ Project.