Antonio López Martín

Interfacial characterization of 2D woven SiC/SiC and cross-ply 0°/90° CAS/SiC composites

A study has been made on the micromechanical behaviour of the interfaces present in two silicon carbide fibre (Nicalon) reinforced ceramic matrix composites: a cross-ply 0°/90° composite with a calcium-aluminium silicate (CAS) glass matrix and a 2D woven composite with a chemical vapour infiltrated silicon carbide matrix. The interfacial properties were determined from fibre push-down tests performed with a nano-indentation system. Several micromechanical models have been fitted to the experimental data to obtain the interfacial mechanical parameters of sliding resistance, debond energy and residual stress. For both materials, the validity of the assumptions of these models is discussed.

Effect of High Strain Rate on the Tensile Behavior of Nicalon™/Cas Continuous-Fiber Ceramic Composites.

The tensile properties of CAS/SiC [(0/90) 3 ] s ceramic matrix composites have been measured as a function of strain rate up to 100 s - 1 . Novel test methods, including the use of piezoelectric transducers as load cells, strain gauges, and high sampling rate data acquisition systems, were set up to ensure accurate measurement of load and strain. Dynamic effects were taken into account when analyzing the stress-strain raw data. It has been observed that the average fracture strength and the average strain energy density are higher with increasing strain rate. This trend is related to the mode of fracture and the damage observed in the composite at different strain rates.