Thermo-elastic properties in short fibre reinforced ultra-high temperature ceramic matrix composites: Characterisation and numerical assessment

The thermo-elastic properties of a novel class of ceramic composites based on an ultra-refractory matrix and containing short carbon fibre to provide failure tolerance and thermal shock resistance were experimentally characterised and numerically simulated. The composites samples were fabricated with fibre volume fractions ranging from 5 to 60 vol% and were featured by homogeneous dispersion of fibre along the basal plane due to the processing route. A random sequential adsorption algorithm was implemented to generate Representative Volume Elements (RVEs), following which finite element (FE) analyses were conducted to determine the elastic modulus and the coefficient of thermal expansion of the composites . Comparison of the experimental and modelling results showed good agreement for the modulus at low fibre volume fractions, and for CTE at higher volume fractions. Discrepancies are attributed to significant evolution of the composite microstructure upon processing at high temperatures, as revealed by microscopic analysis. The observations emphasise the need to account for the effects of microstructural changes on the constituent properties in the modelling of the thermomechanical properties in sintered ceramic composites.

Automated summary

The thermo-elastic properties of a novel class of ceramic composites were characterized and simulated, showing good agreement between experimental and modelling results at low fiber volume fractions but discrepancies at higher fractions due to significant evolution of microstructure at high processing temperatures. The study highlights the importance of accounting for microstructural changes in modelling thermomechanical properties of sintered ceramic composites.