MICROSTRUCTURAL CHARACTERIZATION OF 2-PHASE MATERIALS

Based on the concepts of contiguity and continuous volume, a number of topological parameters have been defined for characterising the micro structure of two phase materials. These parameters can be either deter mined experimentally using standard metallographic methods or calculat ed from the known grain sizes and volume fractions of the constituent phases assuming equiaxed grains and random phase distribution. The com bination of such topological parameters offers an effective descriptio n of phase distribution in a two phase structure having any volume fra ction, grain size, grain shape, and phase distribution. In addition, t he concept of directional contiguity is introduced for the analysis of microstructures oriented along a particular direction. A topological transformation of two phase microstructures has been proposed, which a llows a two phase microstructure having any volume fraction, grain siz e, grain shape, and phase distribution to be replaced by a 'three elem ent body' with three microstructural elements which are aligned in par allel along a particular direction of interest. The transformed three element body is mechanically equivalent to the original microstructure along the aligned direction.