Thermal shock behaviour of angle-ply and woven dense ceramic-matrix composites
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The behaviour of two Nicalon/calcium aluminosilicate ceramic composite laminates (a (±45°)3s and a plain-weave woven) under conditions of thermal shock has been studied. Test specimens heated at various temperatures were quenched into room-temperature water. This was followed by detailed damage characterisation. In addition, post-shock mechanical properties were assessed by tensile tests (for the woven laminate) and flexural tests (for both laminates). Both materials were found to have comparable thermal shock resistance. Crack morphologies comprised matrix cracks of various orientations that exhibited similar characteristics to those described for thermally shocked cross-ply laminates with the same constituents, but cracking was found to be less widespread in the woven laminate. Fibre breaks were also detected on the woven material when high-temperature degradation of the fibre–matrix interface was present. A gradual reduction in properties (stiffness, proportional limit stress, fracture strength) of thermally shocked specimens was identified, which began at larger shocks than those at which thermal shock damage initiated. This was attributed to the extension of some matrix cracks into the bulk of material.
KeywordsThermal Shock Thermal Shock Resistance Matrix Crack Thermal Shock Test Thermal Shock Behaviour
The authors would like to thank Rolls-Royce plc. for the provision of experimental materials. CK acknowledges financial support from the Engineering and Physical Sciences Research Council (UK) and the ‘Alexander S. Onassis’ Public Benefit Foundation. We would also like to thank Dr. Hal Belmonte, Dr. Brian Le Page and, particularly, Mr. Mike Parker, Mr. Peter Haynes and Dr. Nick Ludford for technical assistance and many helpful discussions.
- 2.Kastritseas C, Smith PA, Yeomans JA (2006) In: Ceramic-matrix composites: microstructure, properties, and applications. Woodhead Publishing LtdGoogle Scholar