Composite materials are those formed by two or more components, differentiated at a macroscopic level that are mechanically or chemically united. That is, the components that make it up are visually distinguishable, since it is a heterogeneous mixture and mechanically separable.
However, mixing two materials does not directly lead to the creation of a composite material. For this to happen, there must be a synergy between the components. In other words, the final product has mechanical properties superior to the simple sum of the particular properties of the components . Furthermore, multiphase materials in which the composition of the phases changes during a heat treatment (such as metal alloys) are not considered composite materials.
Currently, we relate composites to cutting-edge and innovative industries and applications, such as aviation, super sports cars or space applications. However, they are products that we can commonly find in almost any everyday scenario and for a long time. Adobe bricks, wood, stone constructions or bones themselves are composite materials.
Did you know that the first known application of composite materials for tool manufacturing was the Japanese Yumi bows?
To manufacture these bows they used bamboo to provide the characteristics of flexibility with pine resin, a component used to stiffen the product. On the other hand, the rope was a compound of hemp, pine resin and vegetable oil.
Returning to the present, we build with reinforced concrete beams and bathe in fiberglass pools, all of this, composite material.
At IBERIA COMPOSITECH we are dedicated to the design and manufacture of fiber-reinforced polymer (FRP) composites, applying the most cutting-edge technologies available . It is for this group of composite materials where the synergy that occurs between the matrix and the reinforcement is most evident.
Properties of composite materials
To the low density of the final product, we must add the high specific properties (higher than those of metals), good dimensional stability and chemical, fire, corrosion and wear resistance. In addition to these characteristics, these composite materials have advantages associated with their conformation, in which we find great flexibility in design at an affordable price.
These composites are made up of a polymer matrix and reinforcement in various shapes and materials. The matrix provides the final product with adhesion properties , compressive strength , hardness , maximum working temperature and visual appearance . While the reinforcement contributes to the characteristics of tensile strength , rigidity , impact resistance and other special properties.
Regarding reinforcements, we can find them in particle or fiber formats. Depending on their length, they are categorized into whiskers for fibers smaller than 1.2 cm; short, less than 6 cm and long. The latter provide the best mechanical properties with respect to the other two. Furthermore, depending on the dimensional arrangement with respect to the part, we will achieve certain properties or others, generating parts with planar anisotropy if required. In this way, the optimization of weight in search of mechanical properties is excellent.
Types of composite materials
The materials used for reinforcements are as diverse as existing applications. Fiberglass, carbon fiber or aramid fiber (Kevlar) are the best known. However, the use of polymeric, ceramic, metallic fibers and especially natural fibers, capable of being recycled, is also interesting.
For polymeric matrices, the type of plastic commonly used is thermoset. This type of polymer degrades when it reaches a certain temperature. On the other hand, we find thermoplastic matrices. The latter, despite having worse mechanical properties, are capable of being melted and re-molded to form another piece.
Composite materials based on thermosets with glass or carbon fibers represent the typical composition of most current applications of composite materials. The continuous optimization of materials and the emergence of new processes have allowed composite materials to enter increasingly demanding sectors that require specific high-tech developments.
In general, the dominant application markets for fiber-reinforced plastics and their relative percentages are the following: automotive sector (23%), civil construction (21%), aeronautics (17%) and sports and recreation (9%). .
The rest is divided into lower consumption applications in the fields of wind energy, medicine, railways, shipbuilding, consumer goods and electronics products.
If you want to delve deeper into the world of composites and their manufacturing processes, in this section we tell you about some of the technologies we work with.