Advantages And Disadvantages Of Composites

CHAPTER 1 INTRODUCTION

1.1 Composites

The individual materials are discrete and distinct within the resulting composite material and are identified macroscopically. This is in contrast to customary metallic alloys whose constituents can be identified only under a high microscopic examination and not macroscopically.

Composite materials are a coalescence of two or more materials with different physical, chemical, mechanical and aesthetic properties. The two constituting materials collaborate to give the composite unique properties.

1.2 Constituents of Composites

Constituent materials are characterized into two types as matrix and reinforcement. Matrix material fortifies and circumvents the reinforcement materials by holding their relative

 Composites possess an excellent cumulation of mechanical, chemical, structural, optical and other desired properties.

 Composite materials are light in weight and possessing high vigor to weight ratio and higher modulus to density ratio then the conventional materials.

 Polymer matrix composites can be moulded toany particular shape and size.

 Anti-corrosion and anti-chemical properties are much lower compared to steel or aluminum. In the current world, fiber- reinforcement composites are superseding products of convectional materials due to low cost and facilitate of engenderment.

1.5 Distinct constraints of composites

Distinct inhibitions of composites are as listed below.

 Composites aren’t economical if the volume of engenderment is less

 Mechanical characterization of a composite structure is more intricate than that of a metal structure. Composites materials are not isotropic, that is, their properties are not same in all the directions. So they require more material

Carbon types are referred to as graphite and are predicated on pitch or polyacrylonitrileprecursor. However, Ceramic type includes alumina, silica, boron, alumina-silica, alumina-boric-silica, zirconia, magnesia, and boron carbide.Thesereinforcements exhibit the phenomenon of size effect on vigor properties of composites.

A less prevalent type of perpetual reinforcement is wire reinforcement. Wires are composed of such metals as Titanium, Tungsten, Molybdenum, Beryllium and Stainless steel. Such wires offer some tailorability good high temperature creep resistance which is an advantage in fighter aircraft jet engines and other aerospace applications.

2.2.2 Discontinuous Reinforcement There are two types of discontinuous reinforcement for MMCs: Particulate and Whiskers. The most mundane types of particulates such as glass, alumina, boron carbide, silicon carbide, titanium carbide, and whiskers of alumina and silicon carbide are widely utilized as