Method of the Analysis of Materials’ Microstructure Based on the Fractal Analysis of Images

Abstract

The basics of metallography and modern systems used to study and analyse the structures of materials are presented. Special attention is paid to the methods of quantitative microscopy. The review of modern computer programs for analysis of image microstructures obtained from digital microscopes is given. The fundamentals of fractal analysis as a highly effective tool for calculating numerical values of parameters of geometrically complex objects are described. The analysis of the graphitized cast iron structure is provided as an example; the application of the fractal analysis method for determining such characteristics of the graphite phase as the shape of graphite inclusions and their distribution in the amount of the alloy is demonstrated. In the course of the research, different classes of cast iron have been studied. To determine the shape of graphite inclusions it was suggested to use fractal dimension. The nonuniformity of the distribution was estimated by such function as lacunarity. The separate stages of determining these characteristics with a specialized FracLac plugin within the ImageJ program are presented. The results obtained have shown high adequacy. In spite of positive assessments, there are shortcomings revealed in the course of the research on the application of fractal analysis methods for identifying geometrically complex dimensional and topological parameters of the graphite phase in cast iron. The ways to further improve these methods in order to solve a wide range of problems in metallography of alloys are suggested.