Microstructure-property relationships of SiC fiber-reinforced magnesium aluminosilicates. 2: Mechanical properties and failure characteristics
- Univ. of Cambridge (United Kingdom). Dept. of Materials Science and Metallurgy
Interfacial frictional shear stresses, flexural properties and failure mechanisms are reported for two magnesium aluminosilicates unidirectionally reinforced with Nicalon SiC fibers. Composites A and B were hot-pressed at 1,500 and 920 C, respectively. High values of interfacial frictional shear stresses inferred from Marshall`s analysis of the micro-indentation technique could be attributed in part to the presence of compressive radial stresses at the fiber-matrix interfaces. Although both composites failed non-catastrophically in symmetrical four point bend testing at room temperature, the failure modes were different. Extensive matrix microcracking, fiber failure and then fiber pull-put were commonly observed in composite A. Failure modes in composite B included the formation of a limited number of matrix cracks, the failure of fibers in the matrix crack front and progressive delamination. The observations demonstrate that the mechanical properties, the interfacial frictional shear stresses and the failure mechanisms of both composites are governed by their microstructural features, in particular the chemistry and structure of the matrix-fiber interfacial region.
- OSTI ID:
- 264109
- Journal Information:
- Acta Materialia, Vol. 44, Issue 7; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
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