Effect of Ductile Phase Reinforcement Morphology on Toughening of MoSi2

1992 ◽  
Vol 273 ◽  
Author(s):  
D. E. Alman ◽  
N. S. Stoloff
Keyword(s):  
Room Temperature ◽  
Matrix Interface ◽  
Short Fibers ◽  
Ductile Phase ◽  
Aligned Fibers ◽  
The Matrix ◽  
Fiber Deformation ◽  
Bend Tests ◽  
Fiber Matrix Interface ◽  
Point Bend

ABSTRACTNiobium was added to MoSi2 in the form of particles, random short fibers and continuous aligned fibers. It was found that the morphology of Nb played a role in the toughening that occurred (as measured by the area under load displacement curves from room temperature three point bend tests and the examination of fracture surfaces). The Nb particles did not toughen MoSi2. The random short fibers appeared to toughen MoSi2 via crack deflection along the fiber matrix interface. Aligned fibers imparted the greatest toughness improvements, as toughening resulted from fiber deformation. However, larger diameter fibers displayed a greater ability to toughen MoSi2 than smaller diameter fibers. This was attributed to the constraint resulting from the interfacial layer between the MoSi2 matrix and the Nb fiber. Maximum toughness occurs when the fiber is able to separate from the matrix and freely deform.

Microstructure and Mechanical Bevavior of Ni3Al-Matrix Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
P. C. Brennan ◽  
W. H. Kao ◽  
S. M. Jeng ◽  
J.-M. Yang
Keyword(s):  
Yield Strength ◽  
Nickel Aluminide ◽  
Fracture Stress ◽  
Room Temperature ◽  
Hot Extrusion ◽  
Matrix Composites ◽  
The Matrix ◽  
Bend Tests ◽  
Point Bend ◽  
Particulate Reinforced

AbstractAn aluminum oxide particulate-reinforced nickel-aluminide composite was fabricated by vacuum hot pressing and hot extrusion. Room temperature three point bend tests were conducted after 1 and 100 h at 1000 °C. The composite exhibited a decrease in yield strength from 772 to 517 MPa after 100 h while the ultimate fracture stress decreased from 1174 to 998 MPa. The strain to failure increased from 4.6% to 6.0% after the same exposure. Saphikon single crystal Al2O3 fibers were used to demonstrate the materials' compatibility. The fracture surfaces of the failed composites indicated ductile failures in the matrix and decohesion between the particles and matrix.

A Study of the Fiber-Matrix Interface in Composite Materials

1992 ◽  
Vol 59 (2S) ◽  
pp. S163-S165 ◽  
Author(s):  
Jin O. Kim ◽  
Haim H. Bau
Keyword(s):  
Composite Materials ◽  
Experimental Technique ◽  
Stress Waves ◽  
Matrix Interface ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Dispersion And Attenuation

A novel experimental technique for studying the characteristics of the interface between the fibers and the matrix in both undamaged and damaged fiber-reinforced composite materials is described. The experimental technique involves the transmission of stress waves in one or more fibers of the composite. The characteristics of the stress waves, such as speed, dispersion, and attenuation, are measured. These measured variables can be correlated with the characteristics of the bonding between the fiber and the matrix.

Prediction of the Fiber-Matrix Interface Failure due to Longitudinal Tensile Loading Using Finite Element Methods

1994 ◽  
Vol 365 ◽  
Author(s):  
Hassan Mahfuz ◽  
A.K.M. Ahsan Mian ◽  
Uday K. Vaidya ◽  
Timothy Brown ◽  
Shaik Jeelani
Keyword(s):  
Local Stress ◽  
Tensile Loading ◽  
Mechanical Tests ◽  
Matrix Interface ◽  
Interface Failure ◽  
Strain Behavior ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Composite Response

ABSTRACTA 3D-unit cell for 0/90 laminated composites has been developed to predict the composite behavior under longitudinal tensile loading condition. 3D contact element has been used to model the fiber matrix interface. Two interface conditions, namely, infinitely strong and weakly bonded, are considered in the analysis. Both large displacement and plastic strain behavior for the matrix are considered to account for the geometric and material non-linearities. Investigations were carried out at three temperatures to compare the composite response obtained from mechanical tests at those temperatures. Stress-strain behavior and the local stress distributions at the fiber as well as at the matrix are presented, and their effects on the failure of the interface are discussed in the paper. The material under investigation was SiCf/Si3N4.

Tensile Properties of Epoxy Composites Reinforced with Continuous Sisal Fibers

2014 ◽  
Vol 775-776 ◽  
pp. 284-289 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Wellington Pereira Inácio ◽  
Artur Camposo Pereira ◽  
Michel Picanço Oliveira
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Epoxy Matrix ◽  
Room Temperature ◽  
Fracture Analysis ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Sisal Fibers

The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of sisal fibers were evaluated. Composites reinforce with up to 30% in volume of long, continuous and aligned sisal fibers were room temperature tested in an Instron machine. The fracture was analyzed by SEM. The results showed significant changes in the mechanical properties with the amount of sisal fibers. These mechanical properties were compared with other bend-tested composites results. The fracture analysis revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties.

The Contribution of Matrix Plasticity to the “Frictional” Sliding of Debonded Fibers in Sapphire-Reinforced TiAl Matrix Composites

1994 ◽  
Vol 350 ◽  
Author(s):  
J. M. Galbraith ◽  
D. A. Koss ◽  
J. R. Hellmann
Keyword(s):  
Material Removal ◽  
Large Scale ◽  
Tial Alloy ◽  
Dominant Role ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Frictional Sliding ◽  
Sic Fiber ◽  
The Matrix ◽  
Fiber Matrix Interface

AbstractLarge-scale fiber displacement behavior, usually characterized by a “frictional” sliding stress (τslide), has been studied in two sapphire-reinforced TiAl systems. Experimental results from fiber pushout and reverse push-back tests indicate that the large-scale sliding behavior of debonded fibers leads to an average τslide-value which progressively decreases during fiber displacements. Previous studies of SCS-6 (SiC) fiber-reinforced glass and metal matrix composites have attributed decreases in τslide to the fracture and wear of fiber asperities. However, given a matrix in which fiber asperities do not easily wear (e.g., a TiAl alloy), SEM examination of the fiber/matrix interface indicates that matrix plasticity plays a dominant role in the decrease of τslide with fiber displacement. Experimental evidence suggests that the observed decrease in τslide can be attributed to (1) a decrease in fiber roughness perceived by the matrix due to matrix grooving and (2) a relaxation of radial clamping as a result of material removal from the interface.

Experimental Investigation of the Interface between Synthetic and Glass Fibers and Lime-Based Mortars

2016 ◽  
Vol 825 ◽  
pp. 57-62
Author(s):  
Michal Přinosil
Keyword(s):  
Experimental Investigation ◽  
Analytical Model ◽  
Glass Fibers ◽  
Fiber Reinforcement ◽  
Pullout Test ◽  
Theoretical Curve ◽  
Matrix Interface ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Displacement Diagram

In this article, the cohesion between fiber reinforcement and lime-based mortar is experimentally investigated using so-called pullout test. The experiment is based on the progressive pulling out of the fiber from the matrix. Comparing the experimental load-displacement diagram with the theoretical curve from the analytical model, the micromechanical parameters describing the fiber-matrix interface are evaluated. In the study, several types of synthetic and glass fibers are considered as well as two types of lime-based mortars. The first one is pure lime, while the second one has lime-metakaolin matrix.

Ductile Phase Toughening of MoSi2-Chemical Compatibility and Fracture Toughness

1990 ◽  
Vol 194 ◽  
Author(s):  
L. Xiao ◽  
Y. S. Kim ◽  
Reza Abbaschian
Keyword(s):  
Fracture Toughness ◽  
Reinforced Composites ◽  
Matrix Interface ◽  
Chemical Compatibility ◽  
Interaction Zone ◽  
Ductile Phase ◽  
Reinforced Composite ◽  
The Matrix ◽  
Mullite Coatings ◽  
Bonding Characteristics

AbstractChemical compatibility between oxide coated Nb filament reinforcements and MoSi2 was investigated. It was determined that ZrO2, Al2O3, and mullite coatings were chemically compatible with both Nb and MoSi2. Comparison between coated and uncoated filaments indicated that the coatings reduced the thickness of the interaction zone. The fracture toughness of the Nb filament reinforced composites showed an increase, while W filament reinforced composite showed a decrease, in the toughness compared to that of the matrix. The results are discussed in terms of the mismatches in the coefficients of thermal expansion and the bonding characteristics of the reinforcement/matrix interface.

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

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
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.

scholarly journals A Review on Natural Fiber-Reinforced Geopolymer and Cement-Based Composites

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4603
Author(s):  
Marfa Camargo ◽  
Eyerusalem Adefrs Taye ◽  
Judith Roether ◽  
Daniel Tilahun Redda ◽  
Aldo Boccaccini
Keyword(s):  
New Technologies ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Industrial Applications ◽  
Synthetic Fiber ◽  
Matrix Interface ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies. In this context, the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites. Natural fibers are renewable, biodegradable, and non-toxic, and they exhibit attractive mechanical properties in comparison with their synthetic fiber counterparts. However, their hydrophilic character makes them vulnerable to high volumes of moisture absorption, thus conferring poor wetting with the matrix and weakening the fiber–matrix interface. Therefore, modification and functionalization strategies for natural fibers to tailor interface properties and to improve the durability and mechanical behavior of cement and geopolymer-based composites become highly important. This paper presents a review of the physical, chemical and biological pre-treatments that have been performed on natural fibers, their results and effects on the fiber–matrix interface of cement and geopolymer composites. In addition, the degradation mechanisms of natural fibers used in such composites are discussed. This review finalizes with concluding remarks and recommendations to be addressed through further in-depth studies in the field.

Fiber-Matrix Bonding in Boron-Reinforced Aluminum Composites

1969 ◽  
Vol 27 ◽  
pp. 32-33
Author(s):  
I. Corvin ◽  
H. Morrow ◽  
O. Johari ◽  
N. Parikh
Keyword(s):  
Aluminum Matrix ◽  
Surface Characteristics ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Boron Fiber ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

A significant amount of research has been done in the past few years in the development of suitable composite materials in general and on boron fiber-aluminum matrix composites in particular. The mechanical properties of the composite depend on the structures and strengths of the matrix and fibers; on the amount, distribution, and surface characteristics of the fibers; and on the quality of the bond at the fiber-matrix interface. The results presented here illustrate the application of the SEM in studying the structure of the fiber-matrix interface and the fracture features of boron and aluminum.

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