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The effect of microstructure on the fracture properties of polycrystalline cubic boron nitride (PcBN) for industrial applications has been investigated numerically using the finite volume method. Representative synthetic microstructures have been created using a modified Voronoi tessellation procedure and these have been implemented in a multi-scale model to investigate the effect of individual microstructural parameters on the bulk material toughness. Crack initiation and propagation has been modelled using an arbitrary crack propagation solver using a cell-centred finite volume based method in FOAM-ext-3.0. The results demonstrate that individual microstructural parameters and their properties, such as percentage grains as well as precise traction–separation relationships between the phases, can greatly influence fracture behaviour and their contributions to the overall fracture toughness of PcBN is quantified and discussed. [ABSTRACT FROM AUTHOR]

Developing an understanding of the dominant failure mechanisms, and identifying the underlying structure–property relationship for polycrystalline diamond (PCD) are of fundamental importance for establishing a roadmap for the future design of materials with improved properties. In this paper, the Finite Volume (FV) method is used to generate representative PCD microstructures based on a diffuse-interface modelling approach. A cell-centred arbitrary crack propagation model is adopted to explore the strength and failure distribution of PCD as a function of the underlying microstructure. In particular, simulations are undertaken to identify the influence of phase morphology and individual constituent properties on the overall fracture strength of PCD. Results indicate that the morphology and distribution of the second phase cobalt relative to grain boundaries have a significant influence on the fracture strength of PCD. The stochastic nature of the strength of the individual grain boundaries was investigated. Larger variation in the distribution of interfacial bond strengths was found to result in a decrease in the overall strength for PCD grades. The effect of removing the cobalt from the microstructure was such that it reduced the overall strength but elevated the sensitivity to grain bond strength distribution. The presented work provides a framework for identifying the salient microstructural features, and offers a means for developing future grades of PCD through targeted virtual material design. [ABSTRACT FROM AUTHOR]

Micromechanical models of two-phase ceramic composites are created using a modified Voronoi tessellation approach. These representative Finite Volume (FV) microstructures are used to investigate the role of microstructure on fracture of advanced ceramics. An arbitrary crack propagation model using a cell-centred finite volume based method is implemented. In particular the effect of matrix content is examined. It is shown that the underlying microstructure significantly affects the local stress and strain distributions for a two-phase ceramic containing hard particles in a softer matrix. Simulation results indicate that an increase in the volume fraction of these hard grains leads to an increase in strength of the composite material. Furthermore, it is found that the homogeneity of the microstructure affects the overall strength. [ABSTRACT FROM AUTHOR]

The effect of microstructure on the strength and toughness of advanced ceramics has been investigated. The current work focuses on numerically modelling statistically representative microstructures and their implementation in multi-scale models. Finite volume based stress analysis is carried out on these microstructures to investigate the effect of individual material parameters on the strength and toughness of the bulk material. From the finite volume analysis it is found that the underlying microstructure affects the local stress and strain distributions within the numerical models. This in turn impacts on the strength and toughness of the bulk material model. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two-dimensional synthetic microstructures are created using a Voronoi tessellation approach. [•] Synthetic microstructures are statistically representative of real microstructures. [•] Finite volume analysis is carried out on the synthetic microstructures. [•] The underlying microstructure affects the local stress and strain distribution. [ABSTRACT FROM AUTHOR]