Investigation on morphology evolution of coarse grained WC-6Co cemented carbides fabricated by ball milling route and hydrogen reduction route

摘要

WC-6Co powders were fabricated via hydrogen reduction and ball milling routes. The influences of powder preparation method on the morphology evolution of WC crystals and mechanical properties of WC-6Co cemented carbide were systemically investigated. In the case of ball milling, some multifaceted WC crystals contained multiple step features and the number of these multi-steps increased with ball milling time. In the case of hydrogen reduction, no multi-steps occurred and the plate-like WC crystals formed. The differences on morphology of WC crystals might be ascribed to the shift of the growth mechanism of WC crystals from a 2D nucleation mechanism to a defect-assisted mechanism. WC-6Co cemented carbide obtained from the hydrogen reduction route showed the improved mechanical properties, a superior combination of hardness, fracture toughness and strength, compared to those obtained from the ball milling route. (C) 2016 Elsevier Ltd. All rights reserved.