Concept of the CPA
Schematic diagram of the model composite used in the
self-consistent effective medium theory, often called
the CPA, or coherent potential approximation.
The true composite is replaced by a large sphere
(dashed circle) containing spherical inclusions of both
type-1 and type-2 constituents in the proper relative proportions.
The matrix (type-*) is composed of a material with adjustable
elastic constants. When there is no net scattering,
the composite and matrix presumably have the same effective
properties.
Another Effective Medium Theory Concept
References