Optimized production route of WC powder pre-alloyed with Ta for fine grained cemented carbides

Powders of hexagonal (W,Ta)C were produced following a two-step carburization process with (W,Ta)(2)C powder as an intermediate product XRD measurements indicate that higher temperatures during the first carburization step increase the fraction of Ta in the (W,Ta)(2)C structure where lower temperatures during the second carburization step seems to increase the fraction of Ta in the (W,Ta)C structure. Lower temperatures during the carburization steps increase the fraction of Sigma 2 WC/WC grain boundaries and cause the formation of what is interpreted as Sigma 4 boundaries. The (W,Ta)C powders can be successfully used to produce fine grained WC-Co based cemented carbides. The pre-alloying with Ta appears to have a softening effect on the material. (C) 2016 Elsevier Ltd. All rights reserved.