Modeling Deformation and Fracture of Boron-Based Ceramics with Nonuniform Grain and Phase Boundaries and Thermal-Residual Stress

A phase field framework of elasticity, inelasticity, and fracture mechanics is invoked to study the behavior ceramic materials. Mechanisms addressed by theory include deformation twinning, dislocation slip, amorphization, anisotropic cleavage fracture. Failure along grain boundaries resolved explicitly, whereWeibull statistics are used characterize surface energies such boundaries. Residual stress incurred mismatching coefficients thermal expansion among phases included. Polycrystalline materials interest ultra-hard ceramics boron carbide (B4C) carbide-titanium diboride (B4C-TiB2), latter a dual-phase composite. Recent advancements in processing technology enable production these via spark-plasma sintering (SPS) at nearly full theoretical density. Numerical simulations invoking biaxial loading (e.g., pure shear) demonstrate how properties mechanisms scale microstructure influence overall strength ductility. In agreement with experimental inferences, show that plasticity more prevalent TiB2 composite reduces tendency for transgranular The demonstrates greater ductility than monolithic B4C both experiments. Toughening brittle from residual stress, addition crack mitigation stronger ductile deemed advantageous attributes