Cemented carbide is widely utilized in cutting tool materials due to its exceptional mechanical properties. Enhancing its performance requires advancements in mechanical properties, though damage typically initiates at the micro-meter scale, highlighting the need for established micro-mechanical strength evaluation methods. This study introduces a micro-mechanical strength evaluation employing micro-cantilevers, successfully quantifying the relationship between microstructural features in the micro-meter range and mechanical strength. We evaluated the effects of the binder metals Co and Ni on the bonding strength at the WC-WC interface, revealing that Co-based cemented carbides exhibit superior strength, thereby enabling a quantitative comparison of their mechanical properties. Additionally, the assessment of WC-WC interface bonding strength in fine-grained cemented carbides containing the grain growth inhibitor VC indicated lower strength for the VC-added carbide compared to the non-added one, suggesting that V segregation disrupts the interfacial structure. Furthermore, in the evaluation of coated cemented carbides, the strength of CVD coated TiCN and Al2O3 was found to be higher in the deposition direction than in the horizontal orientation. This difference was attributed to intra-grain or inter-grain fractures. These findings provide valuable insights for enhancing the performance of cutting tool materials based on the observed microstructural phenomena.
Kido et al. (Thu,) studied this question.