Formation of (W,V)C layers at the WC/Co interfaces in the VC-doped WC–Co cemented carbide

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

“…Both V and Co are segregated at the WC(0001)/WC(0001) interface, which is in good agreement with the results reported by Weidow et al [18]. It seemed that the boundary layer consisted of (V,W)C x , as reported in several papers [10,11]. The Co concentrations at the WC(0001)/Co interface were greater than 60%, even when the centers of the analysis points for XMA were at the WC/(V,W)C x interface.…”

“…These results suggest that the formation of (V,W)C x layers occurs early during sintering and can inhibit WC grain growth [13]. Sugiyama et al reported the presence of (V,W)C x layers at the WC(0001)/Co interface and in the WC grains of an oil-quenched VC-doped WC-Co cemented carbide, which was considered evidence for the existence of the layer before the holding stage during sintering [10]. These results are consistent with those reported by Lay et al [13].…”

“…There are many papers reporting the mechanisms of grain-growth inhibition and the segregation of inhibitors at WC/Co and WC/WC interfaces in WC-Co based cemented carbides with grain growth inhibitors [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. First, on the basis of the theory of crystal growth, Hayashi suggested a mechanism in which WC grain growth is inhibited by dopant adsorption at steps/kinks on the WC grain surface during liquid-state sintering [3].…”

Carbon content dependence of grain growth mode in VC-doped WC–Co hardmetals

“…The interface structures on the sintering state should be observed to understand the authentic grain growth mechanism, but such observation is impossible in slowly cooled specimens. Recently, we found that the cooling rate of oil quenching method is fast enough to freeze up the WC grain/Co phase interface structures on the sintering state [17]. By using this oil quenching technique, we revealed that the (W,V)C x at the WC (0001)/Co forms nano-dots accompanied by planar (W,V)C x sheets at the sintering temperature [18].…”

First-principles study of an interfacial phase diagram in the V-doped WC-Co system

“…Several experimental studies of WC/Co and, in particular, WC(0001)/Co interfaces exist, [16][17][18][34][35][36][37][38][39][40][41][42][43][44] allowing for comparison between model and experiment. In our previous DFT modeling, we found the interface energy between pure VC and Co to be lower than that between WC and Co. 3,27 This energetic difference together with a good parametric fit between VC and WC is the underlying reason for the V segregation to WC/Co interfaces.…”