Recrystallization of submicrocrystalline niobium upon heating above and below the temperature of thermally activated nucleation

摘要

The recrystallization of a niobium submicrocrystalline structure created by high-pressure torsion at room temperature has been investigated. It has been shown that continuous recrystallization begins at just 300A degrees D. It has been characterized by the nonuniform growth of microcrystallites, which prevents the formation of a uniform submicrograin structure. The formation of thermally activated recrystallization nuclei at 900A degrees C increases the nonuniformity of grain size and somehow refines recrystallized grains.