Mechanics of ceramic-epoxy interpenetrating phase composites engineered with TPMS and spinodal topologies

The current contribution investigates the engineering of high strength, ductility and damping interpenetrating phase composites (IPCs), incorporating architected brittle ceramic reinforcement phases in epoxy and whisker-enhanced epoxy matrices. Initially, the mechanical performance of the underlying, ceramic, single-phase triply periodic minimal surface (TPMS) and spinodal metamaterial designs is assessed, quantifying volume fraction and architecture effects. Ceramic-epoxy IPCs can yield more than 30 times higher peak stress values compared to their constituent single-phase ceramic metamaterials, providing an overall ductile rather than brittle response, with substantial strength and deformation capacity. Moreover, whisker-enhanced epoxy matrices furnish considerable improvements in the peak strength and post-elastic performance of epoxy-ceramic IPCs, yielding exceptional Specific Energy Absorption (SEA) attributes, up to 18.5 J/g for 20% ceramic reinforcement phase content IPCs. The effect of the reinforcement phase design is more prominent at lower volumetric contents, leading to considerable differences in strength and energy absorption characteristics. Failure is controlled by the maximum principal stress capacity of the ceramic reinforcement phase, as revealed by dedicated finite element analysis. The remarkable static attributes are combined with outstanding dynamic damping characteristics. The maximum dynamic loss modulus is controlled by the reinforcement phase type and volumetric content, exceeding 500 MPa at 55 Hz for spinodal-based, 30% ceramic reinforcement phase content IPCs, values that outperform the damping capacity of most comparable-strength materials.