Determination of thermal expansion coefficient of particulate composites by the use of a triphase model

In this paper, the thermal expansion coefficient of particle-reinforced composite was determined using a three-phase theoretical model which consists of the transformation of spatial cubic models simulating a particulate composite into a three sphere model, designating the main phases of a composite material the filler and the matrix, in order to apply the classical theory of elasticity to it. Theoretical values derived from three variations of this model were compared with experimental results derived from thermal experiments carried out on iron particle reinforced epoxy resin as well as with theoretical results obtained by other scientists. In this sense an effort has been made to explain on a qualitative as well as on a semiquantitative methodological basis the possible sources which can contribute to the observed discrepancies between theory and experiment. This methodology was based mainly on certain microscopical observations concerning the structural inhomogeneity as well as on theoretical facts the thermal conductivity and capacity of the composite.