Helpful Definitions used in Composites
Composite material. A combination of two or more materials (reinforcing elements, fillers, and composite matrix binder), differing in form or composition on a macroscale. The constituents retain their identities; that is, they do not dissolve or merge completely into one another although they act in concert. Normally, the components can be physically identified and exhibit an interface between one another. (more info.)
Fiber. A general term used to refer to filamentary materials. Often, a fiber is used synonymously with filament. It is a general term for a filament with a finite length that is at least 100 times its diameter, which is typically 0.10 to 0.13 mm. In most cases it is prepared by drawing form a molten bath, spinning, or deposition on a substrate. Fibers can be continuous or specific short lengths (discontinuous), normally no less than 3.2 mm. (more info.)
Filament. The smallest unit of a fibrous material. The basic units formed during drawing and spinning, which are gathered into strands of fiber for use in composites. Filaments usually are of extreme length and very small diameter, usually less than 25 micrometers. Normally filaments are not used individually. some textile filaments can function as a yarn when they are of sufficient strength and flexibility.
Interface. The boundary or surface between two, different physically distinguishable media. On fibers, the contact area between fibers and sizing or finish. In a laminate, the contact area between the reinforcement and the laminating resin.
Interphase. The boundary region between a bulk resin or polymer and an adherend in which the polymer has a high degree of orientation to the adherend on a molecular basis. It plays a major role in the load transfer process between the bulk of the adhesive and the adherend or the fiber and the laminate matrix resin.
Matrix. The essentially homogeneous resin or polymer material in which the fiber system of a composite is embedded. Both thermoplastic and thermoset resins may be used, as well as metals, ceramics, and glasses. (more info.)
Prepreg. The practice of mixing resin and reinforcement and effecting partial cure before use or shipment to the user.
Pultrusion. A continuous process for manufacturing composites that have a constant cross-sectional shape. The process consists of pulling a fiber reinforcing material through a resin impregnation bath and through a shaping die, where the resin is subsequently cured.
Thermoplastic. Capable of being repeatedly softened by an increase of temperature and hardened by a decrease in temperature. Applicable to those materials whose change upon heating is substantially physical rather than chemical and that in the softened stage can be shaped by flow into articles by molding or extrusion. (more info.)
Thermoset. A plastic that, when cured by application of heat or chemical means, changes into a substantially infusible and insoluble material. (more info.)
Whisker A short single crystal fiber or filament used as a reinforcement in a matrix. Whisker diameters range from 1 to 25 micrometers with aspect ratios between 100 and 15000.
Yarn. An assemblage of twisted filaments, fibers, or strands, either natural or manufactured, to form a continuous length that is suitable for use in weaving or interweaving into textile materials.
More helpful information is Here.
Reference:
1)Engineered Materials Handbook; ASM International: Metals Park, 1987; Vol. 1.