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Microstress in Reaction‐Bonded SiC from Crystallization Expansion of Silicon
Author(s) -
Wing Bradley L.,
EsmondeWhite Francis,
Halloran John W.
Publication year - 2016
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/jace.14398
Subject(s) - silicon , materials science , thermal expansion , phase (matter) , composite material , silicon carbide , raman spectroscopy , crystallization , residual stress , metallurgy , chemical engineering , chemistry , optics , physics , organic chemistry , engineering
Microstress in reaction‐bonded silicon carbide ( RBS iC) has been measured using piezo‐Raman spectroscopy. Compressive microstresses as high as 2 GPa exist in the silicon phase and tensile microstresses as high as 2.3 GPa exist in the SiC phase of RBSiC. This is much larger than expected for thermoelastic microstress from coefficient of thermal expansion mismatch would provide. Instead the microstresses arise from the crystallization of liquid silicon. During the reaction bonding process, not all of the silicon reacts to form SiC and there is liquid free silicon. The phase transformation of the free silicon from liquid to solid has a large volume expansion, which results in large residual microstress within the silicon and SiC phases of RBS iC.