Composite Materials                                                                       Composite materials are mixtures of two or more components which are essentially insoluble in each other. The components are usually taken from the fundamental structural materials: metals, ceramics, glasses, polymers.                                                             The properties of composite materials will be determined by the constituents, their relative amounts and the geometry of how they are put together. The result is a material that has superior properties to any of the constituents alone: "The best of both worlds."
Aggregate Composites More or less equi-axed particulates  embedded in a matrix material		Fiber-reinforced Composites Axial particulates embedded in a matrix material			Structural Composites Composites with sophisticated geometries
Dispersion Strengthened                       The particulates are small in size and are present in small concentrations. (<15%)                                      The strength comes from the particulates impeding dislocation motion. Examples include: TD Nickel Thoria (TO2) dispersed in Ni matrix SAP Sintered Aluminum Powder, alumina (Al2O3) coated Al particles dispersed in an Al matrix Al2O3 in Cu Alumina particles dispersed in a copper matrix Al2O3 in Fe Alumina particles dispersed in an iron matrix	Particulate Composites               The particulates are relatively large and are present in large concentrations. (>25% and typcically between 60-90%)           The strength comes from particulates restraining the matrix movement in the vicinity of the particulate. Examples include: concrete asphalt cermets ceramic particles in a metal matrix such as  tungston carbide in cobalt (WC/Co) used for a cutting tool carbon black rubber carbon black in a rubber matrix used for tires	Aligned Fibers           These are either continuous (long) or discontinuous (short). These composites will be highly anisotropic with higher strength in the direction of the fibers.             Continuous fibers make a  stronger composite, but are more expensive and difficult to fabricate.             Examples include: fiberglass wood	Randomly Chopped Fibers         These are randomly oriented short fibers.             They are cheaper and easier to fabricate, however, their properties are usually inferior to that of aligned fiber composites.	Woven Fibers         These fibers are woven in a fabric that is then layered with a matrix material to form a laminate. More expensive but with superior properties.	Examples include: sandwich panals These are made by sandwiching a less dense core material between two thin, strong outer layers.   The core, although not as stiff or strong as the outer layers provides resistance to deformations perpendicular to the faces, and shear rigidity along planes perpendicular to the face.        laminates These are made by 2-dimensional sheets or panels that have a preferred high strength direction.  The layers are stacked and cemented together.

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