P104 Effect of fiber-matrix interface property on fatigue strength in SiC/SiC composites

2005 ◽  
Vol 2005 (0) ◽  
pp. 631-632
Author(s):  
Junji OHGI ◽  
Toshitaka KURAMOTO ◽  
Koichi GODA ◽  
Michiyuki SUZUKI
Keyword(s):  
Fatigue Strength ◽  
Matrix Interface ◽  
Interface Property ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Sic Composites

Mechanical Property Study of the Fiber-Matrix Interface in SiC/SiC Composites

2006 ◽  
Author(s):  
Eric L. Jones ◽  
Sergey Yarmolenko ◽  
Devdas Pai ◽  
Jag Sankar
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Shear ◽  
Fatigue Properties ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Sic Composites

The fiber-matrix interface between ceramic fibers and ceramic matrix plays a major role in the fatigue properties and toughness of continuous fiber reinforced ceramic matrix composites (CMCs). Boron Nitride (BN) is a widely used fiber coating material that provides a weak bond between the fiber and matrix. A weak fiber-matrix interface increases the strength and toughness of the overall CMC. Single fiber push-out tests were performed to study interfacial shear strength as a main parameter defining fatigue properties and toughness of SiC/SiC composites. The fiber-matrix interfacial shear strength was studied in melt infiltrated Hi-Nicalon/BN(CVI)/SiC composites exposed to various temperature and loading conditions, similar to those that are used in actual applications. Hi-Nicalon fibers with diameters of 13-14.5 μm were pushed out from samples with thicknesses ranging from 125-280 μm using a spherical tip with a 1 μm radius and 90° conical shape. Interfacial shear strength was calculated from sliding load, fiber diameter and sample thickness. Due to significant scattering, 30 individual push tests in every sample were used to obtain the average interfacial shear strength. The virgin sample has a shear strength of 20 MPa which is higher than tensile tested samples (12 MPa). Annealing of a virgin specimen for 100 hours at 1000°C slightly increased shear strength up to 21.5 MPa while annealing at 1100°C and 1200°C led to significant increase of shear strength up to 29 and 39 MPa correspondingly. This effect is associated with BN degradation at temperatures >1000°C.

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

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.

Interphase Integrity of Neutron Irradiated SIC Composites

1998 ◽  
Vol 540 ◽  
Author(s):  
L. L. Snead ◽  
E. Lara-Curzio
Keyword(s):  
Fast Neutrons ◽  
Matrix Interface ◽  
Bend Strength ◽  
Tensile Stresses ◽  
Volumetric Expansion ◽  
Residual Stress Analysis ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Sic Composites ◽  
Porous Sic

AbstractSiC/SiC composites were fabricated from Hi-Nicalon™ fibers with carbon, porous SiC and multilayer SiC interphases. These materials were then irradiated in the High Flux Beam Reactor with fast neutrons at 260 and 900–1060°C to a dose of l.1×1025 n/m2 corresponding to 1.1 displacements per atom (dpa). Results are presented for bend strength of both non-irradiated and irradiated materials. Within the interphases studied the multilayer SiC interphase material showed the least degradation (8-20%) in ultimate bend stress, while porous SiC underwent the greatest degradation (∼35%). The fiber matrix interphases are studied with TEM for both non- irradiated and irradiated materials. While no irradiation induced microstructural evolution of the interphase was observed, debonding of the interphase from the fiber was observed for all cases. This debonding is attributed to tensile stresses developed at the interface due to densification of the Hi-Nicalon™ fiber. Residual stress analysis of the fiber matrix interface indicates that the irradiation-induced densification of Hi-Nicalon™ and the volumetric expansion of the CVD SiC matrix cause tensile stresses well in excess of those which can be withstood by these, or any other viable SiC composite interphase.

scholarly journals Rationalizing the impact of aging on fiber–matrix interface and stability of cement-based composites submitted to carbonation at early ages

2016 ◽  
Vol 51 (17) ◽  
pp. 7929-7943 ◽  
Author(s):  
G. H. D. Tonoli ◽  
V. D. Pizzol ◽  
G. Urrea ◽  
S. F. Santos ◽  
L. M. Mendes ◽  
...  
Keyword(s):  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
The Impact

Damping in Unidirectional and Cross-Ply Ceramic Matrix Composites With Matrix Cracks

2001 ◽  
Author(s):  
Victor Birman ◽  
Larry W. Byrd
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Friction ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Unidirectional Composites ◽  
Matrix Cracks ◽  
Dissipation Of Energy ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Abstract The paper elucidates the methods of estimating damping in ceramic matrix composites (CMC) with matrix cracks. Unidirectional composites with bridging matrix cracks and cross-ply laminates with tunneling cracks in transverse layers and bridging cracks in longitudinal layers are considered. It is shown that bridging matrix cracks may dramatically increase damping in unidirectional CMC due to a dissipation of energy along damaged sections of the fiber-matrix interface (interfacial friction). Such friction is absent in the case of tunneling cracks in transverse layers of cross-ply laminates where the changes in damping due to a degradation of the stiffness remain small. However, damping in cross-ply laminates abruptly increases if bridging cracks appear in the longitudinal layers.

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