Fiber-matrix Interface Mechanical Properties of Carbon-Carbon Composites

The mechanical properties of ceramic matrix composites (CMC) depend on the individual properties of fibers and matrix, the fiber-matrix interface, the microstructure and the orientation of the fibers. The fiber-matrix interface of ceramics with stiff matrices (e.g. CVI-derived SiC/SiC) must be weak enough to allow crack deflection and debonding in order to achieve excellent strength and strain to failure (weak interface composites WIC). This micromechanical behavior has been intensively investigated during the last 20 years. With the development of CMC with weak matrices (weak matrix composites WMC) as e.g. oxide/oxide composites or polymer derived CMC the mechanical response can not be explained anymore by these models as other microstructural mechanisms occur. If the fibers are oriented in loading direction in a tensile test the WMC behave almost linear elastic up to failure and show a high strength. Under shear mode or if the fibers are oriented off axis a significant quasiplastic stress-strain behavior occurs with high strain to failure and low strength. This complex mechanical behavior of WMC will be explained using a finite element (FE) approach. The micromechanical as well as the FE models will be validated and attributed to the different manufacturing routes.

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Multiscale Characterization of Nanoengineered Fiber-Reinforced Composites: Effect of Carbon Nanotubes on the Out-of-Plane Mechanical Behavior

Journal of Nanomaterials ◽

10.1155/2017/9809702 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Carlos Medina ◽

Eduardo Fernandez ◽

Alexis Salas ◽

Fernando Naya ◽

Jon Molina-Aldereguía ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Fracture Toughness ◽

Shear Strength ◽

Mechanical Behavior ◽

Matrix Interface ◽

Short Beam ◽

The Matrix ◽

Fiber Matrix Interface ◽

Fiber Matrix

The mechanical properties of the matrix and the fiber/matrix interface have a relevant influence over the mechanical properties of a composite. In this work, a glass fiber-reinforced composite is manufactured using a carbon nanotubes (CNTs) doped epoxy matrix. The influence of the CNTs on the material mechanical behavior is evaluated on the resin, on the fiber/matrix interface, and on the composite. On resin, the incorporation of CNTs increased the hardness by 6% and decreased the fracture toughness by 17%. On the fiber/matrix interface, the interfacial shear strength (IFSS) increased by 22% for the nanoengineered composite (nFRC). The influence of the CNTs on the composite behavior was evaluated by through-thickness compression, short beam flexural, and intraply fracture tests. The compressive strength increased by 6% for the nFRC, attributed to the rise of the matrix hardness and the fiber/matrix IFSS. In contrast, the interlaminar shear strength (ILSS) obtained from the short beam tests was reduced by 8% for the nFRC; this is attributed to the detriment of the matrix fracture toughness. The intraply fracture test showed no significant influence of the CNTs on the fracture energy; however, the failure mode changed from brittle to ductile in the presence of the CNTs.

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Thermal Conductivity of Carbon/Carbon Composites with the Fiber/Matrix Interface Modified by Silicon Carbide Nanofibers

Advances in Chemical Engineering and Science ◽

10.4236/aces.2016.64045 ◽

2016 ◽

Vol 06 (04) ◽

pp. 515-524 ◽

Cited By ~ 1

Author(s):

Jie Chen ◽

Xiang Xiong ◽

Peng Xiao

Keyword(s):

Thermal Conductivity ◽

Silicon Carbide ◽

Carbon Composites ◽

Matrix Interface ◽

Fiber Matrix Interface ◽

Fiber Matrix

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Effects of Thermal Cycling on Properties of Carbon Fiber/Aluminum Composites

Journal of Engineering Materials and Technology ◽

10.1115/1.3226035 ◽

1988 ◽

Vol 110 (2) ◽

pp. 89-95 ◽

Cited By ~ 5

Author(s):

Tetsuyuki Kyono ◽

Etsuro Kuroda ◽

Atsushi Kitamura ◽

Tsutomu Mori ◽

Minoru Taya

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

Thermal Cycling ◽

Degradation Mechanism ◽

Matrix Interface ◽

Aluminum Composites ◽

Longitudinal Tensile Strength ◽

Casting Technique ◽

Fiber Matrix Interface ◽

Fiber Matrix

Effects of thermal cycling on mechanical properties such as longitudinal tensile strength, interlaminar shear strength and work of fracture of carbon fiber/aluminum composites have been investigated. The composite specimens fabricated by a squeeze casting technique were thermally cycled in fluidized baths between room temperature and various temperatures (250, 300, and 350° C) for up to 1000 cycles. The cross sections and fracture surfaces were examined to clarify the degradation mechanism. Significant degradation of the mechanical properties by thermal cycling was observed in untreated carbon fiber/aluminum composites whereas much less degradation in surface treated carbon fiber/aluminum composites. Microscopic observations and short beam shear tests have indicated that the degradation of mechanical properties is caused by debonding at the fiber/matrix interface. The fiber/matrix interface for surface treated fiber was more resistant to debonding. It is concluded that thermal cycling damage of carbon fiber/aluminum composites can be minimized by increasing their fiber/matrix bond strengths.

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Improving mechanical properties of Nextel 610 reinforced Al-224 alloy through θ phase precipitation at the fiber-matrix interface

Materials Science and Engineering A ◽

10.1016/0921-5093(90)90038-5 ◽

1993 ◽

Vol 162 (1-2) ◽

pp. 135-142 ◽

Cited By ~ 6

Author(s):

J.A. Cornie ◽

M.L. Seleznev ◽

M. Ralph ◽

F.A. Armatis

Keyword(s):

Mechanical Properties ◽

Matrix Interface ◽

Phase Precipitation ◽

Fiber Matrix Interface ◽

Fiber Matrix

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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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