Effective interface model for design and tailoring of wc-co microstructures

Interface structures are a key feature in developing modern composite material solutions with ever improved performance. To that effect, we present a nano-microstructural modeling approach for the WC-Co system which can include the interface structures of WC-Co and various other phases present in the microstructure, utilising a methodology which combines imaging based and synthetically generated nano-microstructures into an effective interface model for predicting the behavior and properties of the resulting composite material. The effective model comprises of a local model of the WC-Co interface interacting with a larger scale model of the WC-Co microstructure. The interface model consists of either layered modeling of the different phase structures (phases of WC, films due to doping of cemented carbides, binder phase and microstructure, segregated and carbide structures within the binder such as gamma or eta phases, oriented and/or gradient structures etc.) or utilization of locally defined spatial morphologies and properties in three-dimensional models. In this current work, two approaches are made available and demonstrated. Firstly, commonly identified interface structures can be assessed with the methodology via creation of synthetic carbide-carbide, carbide-binder or related microstructural characteristics. Secondly, the use of phase field analysis generated interface solute concentrations are used as an input from accompanying work by the authors. The results provide a linkage between the interface character of cemented carbide microstructures and their properties, for example with respect to compressive strength, fracture toughness and wear resistance. The results demonstrate the obvious importance of interface character and properties with respect to resulting material properties, and describe a toolset towards systematic inclusion of these features in a materials-by-design type of material development. The methodology presents a multiscale formalism for carrying out performance and application driven evaluation and tailoring of composite interfaces and mesostructures, carried out on the basis of the emerging engineering material properties.