Introduction

A composite material is a material that has a chemically and/or physically distinct phases distributed within a continuous phase. The composite generally has characteristics better than or different from those of either component. The matrix phase is the continuous phase, while the distributed phase, commonly called the reinforcement phase, can be in the form of particles, whiskers or short fibers, continuous fibers or sheet. Figure 1.1 shows the types of composites based on the form of reinforcement. Oftentimes it is convenient to classify different types of composites as per the matrix material characteristics, viz., polymer matrix composites (PMCs), metal matrix composites (MMCs), and ceramic matrix composites (CMCs). The reinforcement in any matrix can be polymeric, metallic, or ceramic. Polymeric matrix composites containing reinforcement fibers such as carbon, glass, or, aramid are quite commonly used as engineering materials. Metals containing ceramic particles, whiskers, or fibers (short or long) are also gaining in importance. The ceramic matrix composites are the newest entrants in the composites field.