In general, today's advanced material applications are subjected to environments and stresses, which benefit from combinations of material properties. For example, in ballistic applications, a material is sought which is lightweight and thus fuel efficient, while at the same time provides great impact absorption properties to prevent injury or mechanical failure to an underlying structure that may be the target of shrapnel or an exploding device. In aircraft or seacraft applications, materials that are strong, light-weight and at the same time corrosion resistant are also sought. In an attempt to achieve these and other material property combinations, composite materials (i.e., multiphase materials) are employed.
There are many types of composite materials. For example, particle-reinforced composite materials, fiber-reinforced composite materials, structural composite materials or layered composite materials are generally well-known. Each type of composite material can include two or more phases wherein one phase makes up the majority of the material and is know as the matrix material and the second phase (and potentially additional phases) make(s) up a lesser extent of the composite and can be dispersed within the matrix material or layered within the matrix material to form a sandwich. The presence of the second and additional phases affects the material properties (such as, for example, the mechanical and thermal properties) of the composite material. That is, the material properties of the composite material are dependent upon the material properties of the first phase and the second phase (and additional phases) as well as the amounts of the included phases forming the composite. Thus, material properties of a composite can be tailored for a specific application by the selection of specific concentrations of the phases, as well as potentially, the sizes, shapes, distribution, and orientation of the included phases.
Difficulties in the formation, durability, and tailoring of material properties have however impeded or prevented the use of composite materials in some applications. For example, material failure may be due, at least in part, to abrupt property changes along phase interfaces.