scholarly journals Stress-dependent matrix cracking in 2D woven SiC-fiber reinforced melt-infiltrated SiC matrix composites

2004 ◽  
Vol 64 (9) ◽  
pp. 1311-1319 ◽  
Author(s):  
Gregory N. Morscher
Keyword(s):  
Matrix Cracking ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Sic Fiber ◽  
Stress Dependent

Effect of fiber coating on creep behavior of SiC fiber-reinforced titanium aluminide matrix composites

1994 ◽  
Vol 9 (1) ◽  
pp. 198-206 ◽  
Author(s):  
Hsing-Pang Chiu ◽  
J-M. Yang ◽  
J.A. Graves
Keyword(s):  
Creep Behavior ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Transverse Loading ◽  
Damage Mechanisms ◽  
Fiber Coating ◽  
Duplex Coating ◽  
Sic Fiber ◽  
Stress Levels

The effect of fiber coating on the creep behavior and damage mechanisms of unnotched SCS-6 fiber-reinforced Ti3Al matrix composites under longitudinal and transverse loading was investigated at 700 °C. Stresses ranging from 700 to 900 MPa and 200 to 400 MPa were used for longitudinal and transverse loading, respectively. An Ag/Ta duplex layer was coated onto the SCS-6 fiber prior to consolidation via physical vapor deposition. The microstructure of the crept composites was examined to determine the creep deformation mechanisms. The creep cracking behavior of the notched composites was also studied at initial stress intensity factors, Ki, ranging from 15 to 20 MPa-m1/2. Microstructural observation revealed that multiple fiber fracture (at low to medium stress levels), microcracking along the reaction zone/matrix interface (at medium stress levels), and matrix cracking extending from the broken fiber ends (at high stress levels) were the major damage mechanisms during quasi-steady state creep under longitudinal loading. The results show that the Ag/Ta duplex coating significantly improved the creep resistance and flexural strength of the composite under transverse loading. The Ag/Ta duplex coating was also shown to significantly prolong the creep rupture life of SiC fiber-reinforced Ti3Al composites.

SiC Fiber Reinforced SiC-Si Matrix Composites Prepared by Melt Infiltration (MI) for Gas Turbine Engine Applications

1999 ◽  
Author(s):  
Gregory S. Corman ◽  
Milivoj K. Brun ◽  
Krishan L. Luthra
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Turbine Engine ◽  
Sic Fiber ◽  
Silicon Melt ◽  
Melt Infiltration ◽  
Near Net Shape

General Electric (GE) has developed silicon carbide fiber reinforced SiC-Si matrix composites by silicon melt infiltration (MI) for use in gas turbine engine applications. This paper focuses on a process based on tow prepreging and lamination of unidirectional tapes. Silicon melt infiltration yields a fully dense, near net shape composite with a relatively high thermal conductivity, actually higher than many superalloys at temperatures up to 800°C, and a high proportional limit, or matrix cracking stress. Room and elevated temperature mechanical properties of the composite are presented. Following exposure to various simulated turbine environments this material shows relatively good retention of strength and toughness. The fabrication of turbine shroud and combustor liner components for high pressure combustion rig testing is also described.

Effect of C/SiC interphase on interfacial and mechanical properties of SiC fiber reinforced mullite matrix composites

2021 ◽  
Vol 98 (2) ◽  
pp. 335-341
Author(s):  
Guihang Deng ◽  
Xun Sun ◽  
Zhenghao Tian ◽  
Ru Jiang ◽  
Haitao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Sic Fiber

Mechanical Behavior of SiC Fiber Reinforced Al Matrix Composites: A Study Based on Finite Element Method

2011 ◽  
Vol 239-242 ◽  
pp. 2785-2789
Author(s):  
Chao Sun ◽  
Min Song ◽  
Ru Juan Shen ◽  
Yong Du
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aspect Ratio ◽  
Plastic Region ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Sic Fiber ◽  
Al Matrix Composites ◽  
Al Matrix ◽  
Element Method

The effects of SiC fiber shape, aspect ratio and loading direction on the deformation behavior of SiC fiber reinforced Al matrix composites were studied by finite element method using axisymmetric unit cell model. The results showed that the addition of reinforcements will cause constraint on the plastic flow of ductile matrix, and thus result in no-uniform stress distribution. The reinforcement shape has a pronounced effect on the overall plastic deformation of the metal matrix composites. The loading condition will cause different failure mechanisms of composites. Under tensile loading, the stress-bearing ability in the plastic region is increased with the fiber aspect ratio due to the increase in the interface between the reinforcement and matrix and the decrease in the inter-particle space.

Monitoring Damage in Non-Oxide Composites at High Temperatures Using Carbon-Containing CVD SiC Monofilament Fibers As Embedded Electrical Resistance Sensors

2020 ◽  
Author(s):  
Ragav P. Panakarajupally ◽  
Joseph Elrassi ◽  
K. Manigandan ◽  
Yogesh P. Singh ◽  
Gregory N. Morscher
Keyword(s):  
Crack Growth ◽  
Electrical Resistance ◽  
Composite System ◽  
Elevated Temperatures ◽  
Ceramic Composites ◽  
Fatigue Tests ◽  
Matrix Cracking ◽  
Fiber Reinforced ◽  
Damage Initiation ◽  
Sic Fiber

Abstract Electrical resistance has become a technique of interest for monitoring SiC-based ceramic composites. The typical constituents of SiC fiber-reinforced SiC matrix composites, SiC, Si and/or C, are semi-conducive to some degree resulting in the fact that when damage occurs in the form of matrix cracking or fiber breakage, the resistance increases. For aero engine applications, SiC fiber reinforced SiC, sometimes Si-containing, matrix with a BN interphase are often the main constituents. The resistivity of Si and SiC is highly temperature dependent. For high temperature tests, electrical lead attachment must be in a cold region which results in strong temperature effects on baseline measurements of resistance. This can be instructive as to test conditions; however, there is interest in focusing the resistance measurement in the hot section where damage monitoring is desired. The resistivity of C has a milder temperature dependence than that of Si or SiC. In addition, if the C is penetrated by damage, it would result in rapid oxidation of the C, presumably resulting in a change in resistance. One approach considered here is to insert carbon “rods” in the form of CVD SiC monofilaments with a C core to try and better sense change in resistance as it pertains to matrix crack growth in an elevated temperature test condition. The monofilaments were strategically placed in two non-oxide composite systems to understand the sensitivity of ER in damage detection at room temperature as well as elevated temperatures. Two material systems were considered for this study. The first composite system consisted of a Hi-Nicalon woven fibers, a BN interphase and a matrix processed via polymer infiltration and pyrolysis (PIP) which had SCS-6 monofilaments providing the C core. The second composite system was a melt-infiltrated (MI) pre-preg laminate which contained Hi-Nicalon Type S fibers with BN interphases with SCS-Ultra monofilaments providing the C core. The two composite matrix systems represent two extremes in resistance, the PIP matrix being orders of magnitude higher in resistance than the Si-containing pre-preg MI matrix. Single notch tension-tension fatigue tests were performed at 815°C to stimulate crack growth. Acoustic emission (AE) was used along with electrical resistance (ER) to monitor the damage initiation and progression during the test. Post-test microscopy was performed on the fracture specimen to understand the oxidation kinetics and carbon recession length in the monofilaments.

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