430 Effect of Heat Treatment on Fiber-Matrix Interfacial Strength in C/C composites

The tension-tension fatigue tests for SiC/SiC composites were performed under the conditions that the maximum load Pmax was 80-90% to the fracture load of the tensile tests and the stress ratio was Rσ = 0.5. The composites exhibited a width in stress-strain hysteresis loop under one load cycling. In some cases the mean strain εmean gradually increase with increasing in number of cycles. These variations would reflect the developments of the fatigue damage at the fiber/matrix interface during the cyclic loading process. The pull-out lengths of the fibers for the fatigued- and not fatigued-specimens were measured through the SEM observations after the tensile test. In all materials, the average pull-out length of fibers in fatigued material was larger than in not fatigued material because the cyclic loading affected on the fiber/matrix interfacial strength.

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Pullout Tests Behavior of Polyester Matrix Reinforced with Malva Fiber

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.371 ◽

2016 ◽

Vol 869 ◽

pp. 371-376 ◽

Cited By ~ 2

Author(s):

Jean Igor Margem ◽

Vinicius Alves Gomes ◽

Frederico Muylaert Margem ◽

Carolina Gomes Dias Ribeiro ◽

Fabio de Oliveira Braga ◽

...

Keyword(s):

Shear Stress ◽

Interfacial Shear Stress ◽

Interfacial Strength ◽

Critical Length ◽

Matrix Composites ◽

Composite Matrix ◽

Pullout Tests ◽

Polyester Matrix ◽

Fiber Matrix ◽

Reinforcing Fiber

The interface between a composite matrix and the reinforcing fiber plays an important role in the efficiency by which an applied load is transmitted throughout the composite structure. The shear stress at the fiber/matrix interface can be associated with this load transference and, consequently, will affect the composite strength. In the present work, pullout tests were used to evaluate the interfacial shear stress of malva fiber in polyester matrix composites. A small critical length was found for the malva fiber embedded in polyester, which corresponds to a relatively weak fiber/matrix bond and lower interfacial strength.

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New Acoustic Emission Analysis for Characterization of Fiber/Matrix Interfacial Strength of Woven Fabric Laminates.

Journal of the Society of Materials Science Japan ◽

10.2472/jsms.45.1131 ◽

1996 ◽

Vol 45 (10) ◽

pp. 1131-1137 ◽

Cited By ~ 1

Author(s):

Toshiyuki UENOYA ◽

Taizo OGURI

Keyword(s):

Acoustic Emission ◽

Interfacial Strength ◽

Woven Fabric ◽

Emission Analysis ◽

Fiber Matrix ◽

Acoustic Emission Analysis

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Fiber strength utilization in carbon/carbon composites: Part II. Extended studies with pitch- and PAN-based fibers

Journal of Materials Research ◽

10.1557/jmr.1995.0609 ◽

1995 ◽

Vol 10 (3) ◽

pp. 609-624 ◽

Cited By ~ 2

Author(s):

Rafael J. Zaldivar ◽

Gerald S. Rellick ◽

J.M. Yang

Keyword(s):

Heat Treatment ◽

Fracture Behavior ◽

Fiber Strength ◽

Fiber Composite ◽

Carbon Composites ◽

High Modulus ◽

Fragmentation Test ◽

Fiber Matrix ◽

The Difference ◽

Very High

Measurements of fiber strength utilization (FSU) in unidirectional carbon/carbon (C/C) composites as a function of heat-treatment tempcrature (HTT) have been extended beyond the original group of DuPont pitch-based E-series fibers to include additional pitch- and PAN-based fibers. Fibers and composites were characterized by tensile strength, optical microscopy, SEM, fiber preferred orientation, and a single-fiber composite (SFC) fragmentation test to provide a relative measure of fiber-matrix interfacial shear strength (IFSS). Results show that fracture behavior and FSU are dominated by the degree of fiber-matrix bonding, as inferred from microscopic observations and measurements of IFSS. In the very high modulus pitch-based fibers, the behavior of the F,130 is strikingly different from that of the Amoco and Nippon Oil fibers, in that it retains good bond strength and high FSU even with HT to 2400 °C, in contrast to the other very high modulus pitch-based fibers that are already weakly bonded at the lowest HTT of 1100 °C. All PAN-based fibers and lower modulus pitch fibers are characterized by strong bonding, brittle fracture, and low FSU for the 1100 °C HTT. Subsequent heat treatment of these composites to 2150 and 2400 °C, in most cases, results in significant recovery of FSU, suggesting an optimum IFSS for each composite. It is suggested that the difference in bonding between the pitch-based E-series and P-series may be related to the similarity in fine structure between the E-fibers and high-modulus PAN-based fibers.

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