EFFECTS OF LAMINA STACKING SEQUENCE ON THE IN- PLANE ELASTIC STRESS DISTRIBUTION OF A PLAIN-WEAVE NICALON FIBER REINFORCED SiC 'LAMINATED COMPOSITE WITH A LAY-UP OF 0/30/60

摘要

Continuous fiber-reinforced ceramic composites (CFCCs) have demonstrated improved toughness and great potential for high-temperature applications.[l-5] Flexure testing is often employed to evaluate the mechanical performance of CFCCs, due to its simplicity and low cost.[6-8] Since no ASTM standard details the test procedure for CFCCs, the test is usually performed in accordance with the ASTM standard for monolithic ceramics. The flexural stress-strain curve of CFCCs shows the extent of toughening and strengthening of the material. The scatter in flexural strength is simply regarded as deviation, which is attributed to the difference in the intrinsic microstructures of CFCCs. One feature microstructural difference between CFCCs and other types (whisker, particulate, short fiber-reinforced) of ceramic matrix composites, (CMCs), is the strong anisotropy behavior of CFCCs. This trend indicates that the in-plane fiber fabric orientation effect could contribute more significantly to the mechanical behavior of the laminated CFCCs than that of CMCs. Understanding this effect definitely could help to minimize the influence of this factor on flexural strength of CFCCs, and will also give a better understanding of the contributions of other dominant parameters, such as properties of fiber/matrix interfacial coatings.