Khripta N. Effect of high frequency impact loading on the structure and functional properties of zirconium-based alloys

The thesis is devoted to development of the physical basis for relaxation-resistant states with in the surface layers of zirconium alloys, which have a high level of corrosion resistance and high strength, obtained by applying advanced techniques of ultrasonic impact treatment of flat samples and wires. Peculiarities of the structural mechanisms of deformation of zirconium alloys were established depending on both the crystal lattice type and the phase composition. A set of factors were found to contribute to the formation of nanoscale structures: a high degree of deformation; formation of compressive stresses with in the surface layers; high-frequency impact pulses; presence of shear strain component under the impaction; local heating during multiple impact deformation. It is found that the complex of physical, chemical, and mechanical properties of zirconium alloys is determined by the structural and phase transformations, redistribution of residual stresses, and by mechanochemical reactions at severe plastic deformation.