The Recovery and Recrystallization Behavior of Cold-Compressed Mo-3Nb Single Crystal

In the present work, the behavior of recovery and recrystallization have been investigated in <111>-oriented Mo-3Nb single crystals cold deformed by uniaxial compression. The macroscopic deformation characteristics and subsequent annealed microstructure evolution of the compressed Mo-3Nb single crystals were carried out by stereomicroscope and electron backscatter diffraction, respectively. Annealed grain boundary misorientation analysis shows Mo-3Nb single crystals no longer keep a monocrystal structure when the compressive strain exceeds 30%. The proportion of high-angle grain boundaries after annealing for Mo-3Nb single crystal with cold compression at high strain rate is larger than that at low strain rate, suggesting that increasing the strain rate can promote the recovery and recrystallization behavior. To elucidate the evolution process of substructure in the recovery and recrystallization, TEM analyses were performed. The annealed dislocation density is reduced and rearranged compared to the cold-compressed state. With the increase of compressive strain, the annealing sub-structure changes from recovery to recrystallization. The recovery process is primarily polygonization, and the mechanism of recrystallization nucleation is through the coalescence of sub-grains.