Disadvantage Of Composite Materials

Historically technical developments have centered around two main areas firstly the development of more powerful and efficient energy sources and secondly to obtain maximum possible motive power from the available energy. The second development is heavily dependent on the properties of engineering materials. In aircraft and aerospace industries, a union of opposites i.e., lightweight in combination with high stiffness is demanded. In pressure vessels technology, high strength and corrosion resistance are both prerequisites for efficient operation. Whenever a designer faces such situations composite materials provide an efficient solution to such problems. The flexibility that can be achieved with composite materials is immense. Merely by changing

The interface is a bounding surface or zone where a discontinuity occurs, whether physical, mechanical, chemical etc. the matrix material must “wet” the fiber. Coupling agents are frequently used to improve wettability. Well “wetted” fibers increase the interface surfaces area. To obtain desirable properties in a composite, the applied load should be effectively transferred from the matrix to the fibers via the interface.

Composite materials can be classified into many categories depending on the type of matrix material, reinforcing material type etc. According to the type of matrix material they can be classified as follows
 Metal matrix type composites: MMC are composited of a metallic matrix (Al, Mg, Fe, Co, Cu).
 Ceramic matrix composites: CMC is material consisting of a ceramic combined with a ceramic dispersed phase. Ex: clay, graphite powder.
 Polymer matrix material: PMC are composed of a matrix from thermosetting (unsaturated polyester, epoxy) or thermoplastic (nylon, polystyrene) and are embedded with glass carbon steel or Kevlar fibers (dispersed phase).
Composite materials can be classified as

This is benefit especially in parts designed for bending stiffness.
• It is a renewable resource, the production requires little energy, and Co2 is used while oxygen is given back to the environment.
• Producible with low investment at low cost, which makes the material an interesting product for low-wage countries.
• Eco-friendly processing, no wear of tooling, no skin problems.
• Thermal recycling is possible, where glass causes problems in combustion furnaces.
• Low impact strength properties.
• Variation in quality, depending on unpredictable influences such as weather.
• Moisture absorption, which causes swelling of the fibers.
• Lower durability, fiber treatment can improve this considerably.
• Poor fire resistance.

Epoxy were introduced, independently by CIBA AG in 1943 and the Devoe and Reynolds Co in 1950.