Segregation layers of grain growth inhibitors at WC/WC interfaces in VC-doped submicron-grained WC–Co cemented carbides

• Published in: International journal of refractory metals & hard materials Vol. 52; pp. 229 - 234
• Main Authors: Kawakami, Masaru, Kitamura, Kozo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2015
• Subjects: Grain growth inhibitor; HRTEM; Interface; Segregation mechanism; Submicron-grained cemented carbide; Grain growth inhibitor; Submicron-grained cemented carbide; Segregation mechanism; Interface; HRTEM
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2015.06.014

The WC/WC interface in VC-doped submicron-grained WC–Co cemented carbides was investigated using high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray microanalysis (XMA) spectroscopy. Both V and Co were segregated at WC(0001)/WC(0001) or WC(0001)/WC(randomly oriented plane) interfaces and were slightly segregated at WC(101¯0)/WC(101¯0) or WC(101¯0)/WC(randomly oriented plane) interfaces. The V concentrations at these interfaces were 6–14at.% and 2–6at.%, respectively, and the Co concentrations were 7–20at.% and 4–28at.%, respectively. The V concentration depended on the WC crystallographic orientation, whereas the Co concentration had a small correlation. On the basis of this result and the previous results for the WC/Co interface, it is concluded that the segregation of V at WC/WC interfaces occurs by the same mechanism as that at WC/Co interfaces. In particular, rather than equilibrium segregation occurring during the heating and holding stages of sintering, segregation onto the WC surface proceeds during the cooling stage of the sintering process. •WC/WC interfaces in a VC-doped submicron-grained hardmetal were investigated.•V segregated at WC/WC interfaces depending on the crystallographic orientation•The layers at WC/WC interfaces were identified as (V,W)Cx layers that include Co.•Layers were deposited from liquid-phase Co onto the WC surface during cooling.