Microstructure-property relationships of SiC fiber-reinforced magnesium aluminosilicates. 2: Mechanical properties and failure characteristics

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(95)00387-8· OSTI ID:264109

Kumar, A; Knowles, K M ^[1]

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1. 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, Journal Name: Acta Materialia Journal Issue: 7 Vol. 44; ISSN XZ504Y; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM SILICATES
COMPOSITE MATERIALS
CORRELATIONS
CRACKS
FAILURES
FLEXURAL STRENGTH
FRICTION
HEAT TREATMENTS
HOT PRESSING
INTERFACES
MAGNESIUM SILICATES
MECHANICAL PROPERTIES
MICROHARDNESS
SILICON CARBIDES
STRESSES