Deformation and plastic coordination in WC-Co composite - Molecular dynamics simulation of nanoindentation

The deformation characteristics and plasticity mechanisms of the WC-Co composite were demonstrated by the molecular dynamics simulations on the atomic scale. It was found that the nucleation, expansion and interaction of dislocations are distinctly dependent on the orientation where the load is applied. At the same indentation depth, the dislocation density in WC is lower by an order of magnitude than in Co. When the indentation is applied on the WC basal plane, the dislocations form firstly on the pyramidal planes and are inclined to slip on the prismatic planes. At the incoherent WC/Co interface in the WC-Co composite, the distortion occurs with loading. In contrast, at the semi-coherent WC/Co interface containing dislocation network, the stress concentration is coordinated, and the nucleation of dislocations in Co is triggered. This is favorable to enhance the resistance against intergranular fracture of the WC-Co composite. (C) 2017 Elsevier Ltd. All rights reserved.