Lugovskoi Y. Regularities of the Influence of the Structure on the Fatigue Characteristics of Composite Metallic Materials

The work is devoted to the determination of regularities of the influence of the structure on the fatigue characteristics of composite metallic materials. On the basis of the thermokinetic and dislocation theories for copper- and nickel-based microcrystalline and microlayered condensed materials, experimental and analytic dependences of the cyclic life on the structural parameters were obtained. On the basis of the Hall-Petch model for microcrystalline materials, experimental and analytic dependences of the fatigue limit and yield point on the minus first power of the mean grain size were obtained. It was shown that this dependence corresponds to the Hall-Petch - type equation provided that the coefficient of this equation is proportional to D-0.5. Analytic dependences of the fracture stress on the cyclic life and size of the structural element were obtained. The influence of the porosity and structural parameters on the fatigue resistance, modulus of elasticity, and decrement of vibrations of highly porous sintered materials on the base of powders, discrete fibers and cell-porous materials was investigated. The dependence of ultimate elastic cyclic strain and fatigue limit on the porosity and structural parameters was calculated. The materials investigated in the present work and known structural materials were analyzed with respect to the vibrodeformability criterion, which was proposed in the work. An advantage of highly porous materials over a copper matrix material in terms of this parameter was shown.