Podcast
Questions and Answers
A composite is considered to be any multiphase ______.
A composite is considered to be any multiphase ______.
material
The properties of composites depend on the properties of the ______ phases.
The properties of composites depend on the properties of the ______ phases.
constituent
The dispersed phase geometry means the ______ of the particles and the particle size, distribution, and orientation.
The dispersed phase geometry means the ______ of the particles and the particle size, distribution, and orientation.
shape
The matrix transfers some of the applied stress to the particles, which bear a fraction of the ______.
The matrix transfers some of the applied stress to the particles, which bear a fraction of the ______.
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The degree of reinforcement or improvement of mechanical behavior depends on ______ bonding at the matrix–particle interface.
The degree of reinforcement or improvement of mechanical behavior depends on ______ bonding at the matrix–particle interface.
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The particles should be small and evenly distributed throughout the ______ matrix.
The particles should be small and evenly distributed throughout the ______ matrix.
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The cermets are examples of ______–metal composites.
The cermets are examples of ______–metal composites.
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For dispersion-strengthened composites, particles are normally much smaller, with diameters between 0.01 and 0.1 µm (10 and 100 ______).
For dispersion-strengthened composites, particles are normally much smaller, with diameters between 0.01 and 0.1 µm (10 and 100 ______).
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Some critical fiber length is necessary for effective strengthening and stiffening of ______ composite material.
Some critical fiber length is necessary for effective strengthening and stiffening of ______ composite material.
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Fibers for which l > lc (normally l > 15lc) are termed ______.
Fibers for which l > lc (normally l > 15lc) are termed ______.
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Study Notes
Introduction to Composites
- A composite is a multiphase material composed of two or more distinct materials, which provides better property combinations.
- A composite material typically consists of two phases: the matrix (continuous phase) and the dispersed phase (filler phase).
Properties of Composites
- The properties of composites depend on the properties of the constituent phases, their relative amounts, and the geometry of the dispersed phase.
- Dispersed phase geometry includes factors such as:
- Concentration
- Size
- Shape
- Distribution
- Orientation
Types of Composite Materials
- Particle-reinforced composites:
- Large particle reinforced: particles are harder and stiffer than the matrix, and tend to restrain movement of the matrix phase.
- Dispersion strengthened: particles are much smaller, and particle-matrix interactions occur on the atomic or molecular level, leading to strengthening.
- Fiber-reinforced composites:
- Critical fiber length (lc) is necessary for effective strengthening and stiffening.
- Fibers can be classified as continuous (l > lc) or discontinuous (short fibers).
Characteristics of Composites
- Cermets are examples of ceramic-metal composites, used as cutting tools or in dentistry.
- The elastic modulus of a two-phase composite depends on the volume fraction of the constituent phases, and can be predicted by the rule-of-mixtures equations.
Stiffening and Strengthening
- In particle-reinforced composites, strong bonding at the matrix-particle interface is necessary for effective reinforcement.
- In dispersion-strengthened composites, small dispersed particles hinder the motion of dislocations, leading to improved yield and tensile strengths, as well as hardness.
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Description
This quiz covers the basics of composites, including their definition, properties, and composition. Learn about the principle of combined action and the roles of the matrix and dispersed phases.
