Basic elements › Materials

COMPOSITE MATERIALS

These are materials designed by combining two or more chemically distinct substances — generally a die and a reinforcement — in order to obtain mechanical or physical properties superior to those of each component taken individually. The resulting substance typically exhibits increased strength, increased durability, remarkable lightness, or other characteristics specific to the intended application.

The watchmaking industry has integrated composite materials as part of an approach aimed at lightening, stiffening, and increasing resistance to shocks and chemical agents.

Basic principle

The founding idea of the composite Material is that thecombination of two Materials can exceed the simple addition of their respective qualities. The Die — often a polymer resin, a Metal or a Ceramics — ensures the cohesion of the whole and distributes mechanical stresses, while the reinforcement — fibres, particles or woven structures — provides rigidity, strength or other targeted properties.

This principle is not new: reinforced concrete, which combines concrete (resistant to compression) andSteel (resistant to tension), constitutes its most universal example. In nature, the Wood is itself a composite, assembling cellulose fibres in a lignin Die.

Main families

There are generally three main families, depending on the nature of the die:

• Polymer matrix composites (PMC): in particular carbon or glass fibres embedded in an epoxy resin, the most widespread in the industry, as they are very light and strong.
• Ceramic matrix composites (CMC): designed for extreme environments (high temperatures, intense abrasion).
• Metal matrix composites (MMC): combine a light Metal (Aluminium, Titanium) with ceramic reinforcements. They tolerate high temperatures better than PMCs.