To create new constructing materials, one should know mechanical properties and fracture features of individual structural constituents of those materials. The technique to evaluate strain-hardening diagrams of individual structure constituents in multi- component systems using microhardness data was developed.The data obtained using the new experimental technique are used in the generalized model of plastic flow of a multiphase material. Electron microscope investigations of early fracture stages of separate structural constituents in a multiphase material were performed.