Structure of chromium-zirconium bronze subjected to dynamic channel-angular pressing and aging

Structure changes in chromium-zirconium bronze upon high-speed deformation and subsequent annealing have been studied using the methods of metallography and electron microscopy and microhardness measurements. Deformation was performed by the method of dynamic channel-angular pressing in one and three passes. The deformation creates a submicrocrystalline structure and increases the microhardness by 2.4 times. Aging additionally increases the microhardness by 10%. During annealing at temperatures of 400–700°C, aging and recrystallization take place. At early stages of aging, nanosized particles pin dislocations, thus hampering the formation of recrystallization centers. At subsequent stages, chromium particles impede the migration of large-angle boundaries, thereby blocking the development of recrystallization. At the beginning of aging process in the deformed structure, chromium particles are coherent with the copper matrix and have an fcc structure. Upon the coarsening of the particles in the recrystallized structure, they acquire a bcc structure that is typical of chromium.