Microstructure and mechanical properties of ultrafine-grained hardmetals

• Published in: International journal of refractory metals & hard materials Vol. 19; no. 4; pp. 553 - 559
• Main Authors: Sailer, T., Herr, M., Sockel, H.-G., Schulte, R., Feld, H., Prakash, L.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2001
• Subjects: Bending strength; Complex binder systems; Fatigue behaviour; Microstructure; Ultrafine-grained hardmetals; Bending strength; Fatigue behaviour; Complex binder systems; Microstructure; Ultrafine-grained hardmetals
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/S0263-4368(01)00041-5

The interest in ultrafine-grained hardmetals as woodcutting tool materials derives from their excellent mechanical properties compared with those of conventional hardmetals. The aim of this work was to determine the mechanical properties of ultrafine-grained hardmetals and to correlate the measured effects with microstructural parameters. The ultrafine-grained hardmetals (WC grain size ⩽0.3 μm) investigated consisted of different WC powders and different binder systems: Co and complex binder systems. The mechanical properties of ultrafine-grained hardmetals were tested under two different loading conditions: monotonically increasing and cyclic alternating bending loads. It could be shown that the binder systems of different compositions show different behaviours under cyclic loads. Ultrafine-grained hardmetals with Co binder exhibit high bending strength values, but high fatigue sensitivity. Ultrafine-grained hardmetals with complex binders show lower bending strength values but their sensitivity to fatigue is lower. This implies that different damaging mechanisms exist for ultrafine-grained hardmetals with Co and complex binders.