AE Characterization of Bending Fracture Behavior in 3D-woven SiC/SiC Composites Fabricated by Multiple Polymer Impregnation Pyrolysis Process

SiC fiber reinforced SiC matrix (SiCf-SiC) composites with and without pyrolytic carbon interphase were prepared by polymer impregnation pyrolysis (PIP) progress. The effect of pyrolytic carbon interphase on the fracture behavior and mechanical properties of SiCf/SiC composites was studied. The results show that pyrolytic carbon interphase weakened the bonding between the matrix and the fibers. The mechanical properties of SiCf-SiC composites with carbon coating were improved effectively via fiber debonding and pulling-out from matrix under external loads. The flexural strength and fracture toughness of the above composites reached up to 498.52MPa and 24.09MPa•m1/2, respectively.

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Characterization of Fiber-Reinforced SiC Composites by Precursor-Pyrolysis and Hot-Pressing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.1305 ◽

2007 ◽

Vol 280-283 ◽

pp. 1305-1308

Author(s):

Xin Bo He ◽

Xuan Hui Qu ◽

Chang Rui Zhang ◽

Xin Gui Zhou

Keyword(s):

Mechanical Properties ◽

Hot Pressing ◽

Fracture Behavior ◽

Matrix Interface ◽

Direct Reactions ◽

Fiber Matrix Interface ◽

Fiber Matrix ◽

Sic Composites ◽

Strength Retention

CF/SiC and Hi-Nicalon/SiC composites were prepared by precursor pyrolysis-hot pressing, and the microstructure and fracture behavior of the composites were investigated. Because of a strongly bonded fiber/matrix interface primarily resulting from the direct reactions between the fibers and matrix, Hi-Nicalon/SiC composite exhibited a typical brittle fracture behavior. However, CF/SiC composite displayed a tough fracture behavior with extensive fiber pullout, which was primarily attributed to a weakly bonded fiber/matrix interface as well as higher strength retention of the fibers. As a result, CF/SiC composite achieved better mechanical properties of 691.6 MPa in strength and 20.7 MPa•m1/2 in toughness, which were much higher than those of Hi-Nicalon/SiC composite.

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CHARACTERIZATION OF LIQUID PHASE SITERED SIC AND SIC/SIC COMPOSITE MATERIALS

International Journal of Modern Physics B ◽

10.1142/s0217979210065854 ◽

2010 ◽

Vol 24 (15n16) ◽

pp. 2916-2921 ◽

Cited By ~ 2

Author(s):

MOON HEE LEE ◽

SANG PILL LEE ◽

KWAN DO HUR

Keyword(s):

Liquid Phase ◽

Flexural Strength ◽

Fracture Behavior ◽

Sintered Density ◽

Secondary Phase ◽

Sintering Additives ◽

Catastrophic Fracture ◽

Sic Composites ◽

Composition Ratios

The characterization of liquid phase sintered(LPS) SiC based materials has been investigated with the analysis of microstructure and flexural strength. Especially, LPS - SiC materials were examined for the variation of test temperature and composition ratios ( Al 2 O 3,/ Y 2 O 3) of sintering additives. LPS - SiC based materials were fabricated by hot pressing(HP) associated with the liquid phase formation of sintering additives( Al 2 O 3, Y 2 O 3). LPS - SiCf / SiC composites were also fabricated with plane-woven(PW) Tyranno-SA fibers without an interfacial layer. LPS - SiC materials showed a dense morphology with the creation of the secondary phase like YAG. The composition ratio of sintering additives led to the variation of sintered density and flexural strength. The flexural strength of LPS - SiC materials was greatly decreased at the temperature higher than 1000°C. LPS - SiCf / SiC composites represented an average flexural strength of about 260 MPa, accompanying the catastrophic fracture behavior without any full-out phenomena.

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