Composite Material
Introduction
Composite materials, or composites, are materials made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials.
History
The history of composite materials dates back to ancient times for construction applications; straw was mixed with mud to build walls, as the straw improved the strength and durability of the wall. In the 20th century, composite materials were developed with more complex structures for advanced applications. For example, a combination of wood and plastic was developed in the 1960s for use in boat hulls, and the first all-composite airplane, the Boeing 787 Dreamliner, was flown in 2009.
Types of Composites
Composite materials are generally classified into two groups: Fiber-reinforced composites and Particle-reinforced composites.
Fiber-Reinforced Composites
Fiber-reinforced composites are composed of fibrous materials embedded in a matrix material. The fibers provide strength and stiffness to the composite and can be continuous or discontinuous, long or short, oriented randomly or in a specific direction. Examples of fiber-reinforced composites include fiberglass, carbon fiber composites, and aramid fiber composites.
Particle-Reinforced Composites
Particle-reinforced composites have dispersed phase materials in a different material matrix. The dispersed phase is typically harder and stronger than the matrix, resulting in a composite material that has improved mechanical properties. Examples of particle-reinforced composites include cement (sand and gravel reinforced with cement), cermets (ceramic and metal), and tungsten carbide (cobalt-reinforced tungsten carbide).
Properties of Composites
Composite materials exhibit unique properties that can be tailored to meet specific design requirements. These properties include high strength and stiffness, low weight, resistance to chemical attack, and durability in harsh environments.
Strength and Stiffness
The strength and stiffness of a composite material are primarily determined by the type, orientation, and volume fraction of the reinforcing fibers. By carefully selecting and arranging the fibers, the mechanical properties of the composite can be tailored to meet specific design requirements.
Weight
Composite materials are often lighter than traditional materials, such as metals, because the density of the reinforcing fibers is typically lower than the density of the matrix material. This makes composites an attractive option for applications where weight is a critical factor, such as in the aerospace and automotive industries.
Chemical Resistance
Composites are resistant to a wide range of chemicals, including acids, alkalis, and solvents. This makes them suitable for use in harsh environments, such as in the chemical industry or in outdoor applications.
Durability
Composites are durable materials that can withstand harsh environmental conditions, including high temperatures, high pressures, and corrosive environments. This makes them suitable for use in a wide range of applications, including aerospace, automotive, marine, and industrial applications.
Applications of Composites
Composite materials are used in a wide range of applications, from everyday items to sophisticated aerospace applications. Some of the key applications of composite materials include:
Aerospace Applications
Composite materials are extensively used in the aerospace industry due to their high strength-to-weight ratio and excellent resistance to environmental conditions. They are used in the manufacture of aircraft structures, such as wings and fuselages, as well as in the production of spacecraft components.
Automotive Applications
In the automotive industry, composite materials are used in the production of body panels, interior parts, and structural components. They offer several advantages over traditional materials, including weight reduction, improved fuel efficiency, and increased design flexibility.
Marine Applications
Composite materials are used in the marine industry in the construction of boat hulls, decks, and masts. They offer several advantages over traditional materials, including improved durability, resistance to corrosion, and reduced maintenance requirements.
Industrial Applications
In industrial applications, composite materials are used in the manufacture of pipes, tanks, and other equipment. They offer several advantages over traditional materials, including improved durability, resistance to corrosion, and reduced maintenance requirements.
Future of Composites
The future of composite materials is promising, with ongoing research and development aimed at improving the properties and reducing the cost of these materials. Advances in manufacturing techniques, such as additive manufacturing, are expected to enable the production of complex composite structures with improved performance and reduced weight. In addition, the development of new types of composite materials, such as nanocomposites, is expected to open up new opportunities in a range of industries.