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SiC‐Whisker‐Reinforced Glass‐Ceramic Composites: Interfaces and Properties
Author(s) -
Brennan John J.,
Nutt Steven R.
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb05559.x
Subject(s) - materials science , composite material , whisker , fracture toughness , whiskers , flexural strength , scanning electron microscope , composite number , toughness , ceramic , ceramic matrix composite , auger electron spectroscopy , physics , nuclear physics
Different types of SiC whiskers were incorporated into lithium aluminosilicate (LAS) and calcium aluminosilicate (CAS) glass‐ceramic matrices. Interfaces in these composites were characterized using Auger spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the observations were correlated with measurements of fracture toughness and strength. The chemistry and morphology of the resulting interfaces affected the composite strength and toughness and controlled the mode of crack propagation. Certain types of SiC whiskers were characterized by a carbon‐rich near‐surface chemistry that became more carbon rich after composite fabrication. In these materials, the flexural strength at 20°C increased by up to 400% and the fracture toughness increased by up to 500%. Crack propagation modes were characterized by crack deflection, whisker–matrix debonding, and crack bridging. In contrast, SiC whiskers with stoichiometric near‐surface chemistry generally did not form carbon‐rich interfaces during composite fabrication, resulting in composites with low strength and fracture toughness.