Composite Materials

Vocabulary flashcards covering the definitions, types of matrix and reinforcement materials, and interface properties of composite materials as presented in the lecture.

Composite

A material deliberately made from a combination of more than one constituent, where the combination gives advantages in properties.

Matrix

The constituent in a composite whose main roles are to transfer stress between reinforcing fibres or particles, provide toughness, and improve processibility.

Metal Matrix Materials

Commonly aluminium, magnesium, or titanium alloys with densities between $3,000 - 5,000\,kg/m^3$ and temperature resistance up to $800^\circ\text{C}$, offering good toughness and strength.

Ceramic Matrix Materials

Materials like Alumina, Zirconia, Silicon Carbide, and Silicon Nitride with densities of $2,000 - 3,000\,kg/m^3$ and very good temperature resistance up to $1300^\circ\text{C}$, but poor toughness.

Thermosetting Polymers

Matrix materials such as epoxies, polyesters, and phenolics with densities of $1,000$ to $1,300\,kg/m^3$, poor temperature resistance up to $250^\circ\text{C}$, and moderate toughness.

Thermoplastic Polymers

Matrix materials like polypropylene, nylons, and PEEK with densities of $980 - 1,300\,kg/m^3$, excellent toughness, but the lowest strength among matrix types.

Particulate Reinforcements

Constituents whose main roles are to increase stiffness, increase hardness, reduce cost, and modify properties such as density, conductivity, or magnetic behavior.

Fibre Reinforcements

Constituents whose main roles are to increase stiffness, increase strength, and increase toughness.

Glass Fibres

Low cost reinforcement offering good stiffness, reasonable strength, and good temperature resistance, but low toughness.

Carbon Fibres

Expensive reinforcement characterized by good stiffness and strength, moderate toughness, and moderate temperature resistance.

Polyaramids

Materials such as Kevlar which are quite expensive and offer moderate stiffness and strength with excellent toughness.

Ceramic Whiskers

Short fibres such as Silicon carbide, Boron, or Aluminium oxide that provide high stiffness and high temperature resistance but low toughness.

Carbon Nanotubes

Very small, very expensive fibres with very high strength, very high stiffness, and good toughness.

Natural Fibres

Mainly plant-based (cellulose) materials like hemp, jute, or sisal that have high levels of water absorption and generally lower environmental impact.

Interface

The surface between the reinforcement and the matrix.

Interphase

The region of the matrix close to the reinforcement which can differ in cure levels, crystallinity, microstructure, or stresses; vital for stress transfer.

Continuous Unidirectional Arrangement

A complex fibre arrangement where long fibres are oriented in a single direction to optimize properties in that axis.