Abstract Practical application of new materials made by PM technologies requires, like in the case of wrought material, a lot of information concerning their properties. Based on these data the material behaviour under defined conditions can be predicted. Mainly mechanical properties, which control the application possibilities of the material, attract the interest in the case of structural materials. According to the presumed application the new developed material is tested with the aim to analyse its strength, plasticity, or fatigue properties. The mechanical properties and the behaviour of the material under defined loading conditions is a function of its microstructure. Recognising and describing this relation means to find out the deformation and fracture mechanisms of the investigated material. The analytical description of mechanisms resulting in fracture enables to create a model for predicting the material behaviour in the loading process and thus to determine the boundary conditions for the application of examined material in the technical practice. The process of developing such a model has two basic steps: a) generating a model of the microstructure b) creating a physical model of the crack propagation The model microstructure can be obtained from the basic characteristics of the real microstructure of investigated material which can be evaluated by image analysis followed by mathematical processing. The physical model of crack propagation is based on the theory of fracture mechanics and on the fractographic analysis of the crack. The presented paper deals with methods creating the model microstructure. The procedure of image analysis and its mathematical processing necessary for noise removing and trash holding of the microstructure components are described. Voronoi mosaic generation was chosen for developing the heterogeneous model microstructure.