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Superplastic Deformation in Silicon Nitride–Silicon Oxynitride In Situ Composites
Author(s) -
Xie RongJun,
Mitomo Mamoru,
Zhan GuoDong,
Emoto Hideyuki
Publication year - 2000
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.1151-2916.2000.tb01586.x
Subject(s) - superplasticity , materials science , microstructure , composite number , composite material , silicon nitride , ductility (earth science) , deformation (meteorology) , silicon oxynitride , silicon , phase (matter) , fracture toughness , texture (cosmology) , toughness , metallurgy , creep , chemistry , organic chemistry , image (mathematics) , artificial intelligence , computer science
Starting with a mixture of ultrafine β‐Si 3 N 4 and a SiO 2 ‐containing additive, a superplastic Si 3 N 4 ‐based composite was developed, using the concept of a transient liquid phase. Significant deformation‐induced phase and microstructure evolutions occurred in the nonequilibrium, fine‐grained Si 3 N 4 material, which led to the in situ development of a Si 3 N 4 –22‐vol%‐Si 2 N 2 O composite and strong texture formation. The unusual ductility of the composites with elongated Si 2 N 2 O grains was attributed to the fine‐grained microstructure, the presence of a transient liquid phase, and the alignment of the elongated Si 2 N 2 O grains. The mechanical properties of the resultant composite were enhanced rather than impaired by superplastic deformation and subsequent heat treatment; the resultant composite exhibited both high strength (957 MPa) and high fracture toughness (4.8 MPa·m 1/2 ).