Metal Matrix Composites - Why Composites??????

Composites have been normally designed and manufactured for applications in which high performance and light weight are needed. There other several advantages over traditional engineering materials as discussed below.

1. Composite materials provide capabilities for part integration. Several metallic components can be replaced by a single composite component. This others greater exibility for design changes in this competitive market where product lifetime is continuously reducing and eliminates several machining operations and thus reduces process cycle time and cost.

2. Composite materials other greater feasibility for employing Design for Manufacturing (DFM) and Design for Assembly (DFA) techniques. These techniques help minimize the number of parts in a product and thus reduce assembly and joining time. Noise, Vibration and Hardness (NVH) characteristics are better for composite materials than metals.

3. Composite structures provide in-service monitoring or online process Monitoring with the help of embedded sensors. This feature is used to monitor fatigue damage in aircraft structures or can be utilized to monitor the resin ow in Resin Transfer Molding (RTM) process. Materials with embedded sensors are known as "smart" materials, can also be fabricated using composite structures.

4. Composite materials have a high specific stiffness (stiffness-to-density ratio) and the specific strength (strength-to-density ratio). The fatigue strength (endurance limit) is much higher for composite materials.

5. Composite materials other high corrosion resistance. Iron and aluminum/ aluminum alloys, however, corrode in the presence of water and air and require special coatings.

6. The Coefficient of Thermal Expansion (CTE) of composite structures can be made zero by selecting suitable materials and lay-up Sequence. As the CTE for composites is much lower than for metals, Composite structures provide good dimensional stability and manufacturing feasibility.