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Microstructure and Mechanical Properties of Hot‐Pressed Silicon Carbide‐Aluminum Nitride Compositions
Author(s) -
Xu Youren,
Zangvil Avigdor,
Landon Martine,
Thevenot François
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.tb08182.x
Subject(s) - materials science , microstructure , grain size , grain growth , silicon carbide , flexural strength , phase (matter) , metastability , nitride , diffusion , composite material , metallurgy , chemistry , layer (electronics) , physics , organic chemistry , thermodynamics
A flexural strength of up to 1 GPa was achieved in SiC‐AIN materials and is attributed to a dense, equiaxial grain structure of the 2H(δ) SiC‐AIN solid solution, with a relatively uniform grain size of ∼ 1 μm. The strength was found to decrease with increasing grain size. While the β→α phase transformation and the formation of various metastable polytypes make microstructural control difficult in SiC materials, excellent control is facilitated in SiC‐AIN materials as a result of the stable 2H solid solution. Several mechanisms of grain refinement during the β→ 2H transition were observed, most notably the direct formation of several 2H grains from a single β grain. In addition, grain growth is limited by the diffusion‐controlled nature of the transition. These mechanisms could be utilized to achieve even higher strength values, with potentially higher reliability of the materials in structural applications.