Modeling the solidification microstructure and mechanical response of WC-Co coatings

Thermal spray deposition is indirectly controlled and challenging to diagnose, and the significance of different microstructural features can be hard to identify through traditional characterization methods. Modeling can be used to  virtually diagnose the deposition, and to systematically study different features and application performance of the final coating microstructure.

As a case study we show how specific microstructural features of a WC-Co coating lead to the material failure. Special attention is paid to the WC-Co interfacial region. An SEM image of WC-Co powder is segmented into different phases, followed by a simulation of WC dissolution in flight. This is used as an initial condition for a solidification simulation with the phase-field method. Consequently, the mechanical performance of the simulated solidification microstructure is studied with respect to wear resistance. The bulk WC and Co phases, and the interfacial region, are all assigned with their own material models via multiscale modeling.