What are composite materials?

The importance of composite materials

Different type of composites

Disadvantages of composites





What are composite materials?

Composites are a unique class of materials made from two or more distinct materials that when combined are better (stronger, tougher, and/or more durable) than each would be separately. They are non-corroding, non-magnetic, radar transparent and they are designed to provide strength and stiffness where it is needed.

Although many man-made materials have two or more constituents, such as metallic alloys, but they are usually not classified as composites because the structural unit is formed at microscopic level (it means that the combination of materials are combined in such a way that the individual components are indistinguishable) rather than at the macroscopic level (that means the constituents retain their identities in the composite, they do not dissolve or otherwise merge completely into each other). In composite materials, the components can be physically identified and exhibit an interface between one another.

The most common composite is the fibrous composite consisting of reinforcing fibres embedded in a binder, or matrix materials.back to top




The importance of composites

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Composites have properties, which could not be achieved by either of the constituent materials alone. We can see that composites are becoming more and more important as it can help to improve our quality of life. Composites are put into service in flight vehicles, automobiles, boats, pipelines, buildings, roads, bridges, and dozens of other products. Researchers are finding ways to improve other qualities of composites so they may be strong, lightweight, long-lived, and inexpensive to produce.back to top


Different type of composites

Actually the production of composites is an attempt to copy nature. Wood is a composite of cellulose fibres cemented together with lignin. This kind of composite is called natural composites.

And for man-made composites, there are polymer matrix composites (PMCs), metal matrix composites (MMCs) and ceramic matrix composites (CMCs). They are made from adding reinforcing fibres into polymer matrix, metal matrix or ceramic matrix respectively.

Polymer Matrix Composites (PMCs) - These are the most common and will be the main area of discussion in this website. Also known as FRP - Fibre Reinforced Polymers - these materials use a polymer-based resin as the matrix, and a variety of fibres such as glass and carbon as the reinforcement. For example fibreglass, the first successful modern composites, is one of the polymer matrix composites. It is used for making boat hulls, storage tanks, pipes, and car components.

Metal Matrix Composites (MMCs) - Increasingly found in the mobile  industry, these materials use a metal such as aluminium as the matrix, and reinforce it with fibres such as silicon carbide.

Ceramic Matrix Composites (CMCs) - Used in very high temperature environments, these materials use a ceramic as the matrix and reinforce it with short fibres, such as those made from silicon carbide and boron nitride. back to top



Disadvantages of composite materials

Although composite materials have certain advantages over conventional materials, composites also have some disadvantages. The common one is the high manufacturing costs. However, as improved manufacturing techniques are developed, it will become possible to produce composite materials at higher volumes and at a lower cost than is now possible.back to top