Strength and reinforcement of interfaces in cemented carbides

The tendency for segregation of 3d-transition metals to WC/WC interfaces in cemented carbides, and resulting effect on grain boundary cohesion, have been assessed by density-functional theory calculations. The results show that the propensity for segregation increases along the 3d-series, both to free carbide surfaces and to carbide–carbide interfaces. The tendency for metal substitution in W-rich boundaries is very low while 3d atoms readily segregate to C-rich boundaries by carbon substitution. The strengthening effect on grain boundary cohesion in the latter case is largest for V, Cr, and Mn, but is substantial for all segregants in this study.