Recrystallization behavior of a heavily cold-rolled Ni3Al(B,Zr) alloy

The present article describes the microstructural changes during recrystallization annealing of a 73 pct cold-rolled Ni3Al(B,Zr) alloy along with a study of the recrystallization kinetics. The deformed γ regions, mostly within and near the shear bands, appear to recrystallize first. The recrystallization front leaves behind a lamellar discontinuous precipitation within the newly formed strain-free γ grains, when annealing is done at lower temperatures. At higher annealing temperatures, the precipitates within γ assume a globular morphology. This precipitate is presumably made up of γ′ particles. When γ recrystallization is nearly complete, the γ′ regions start to recrystallize. The two-stage recrystallization process is also corroborated from the kinetics results, which show that the activation energy up to 50 pct recrystallization of the material is only 117 kJ/mole, whereas beyond 50 pct until the completion of recrystallization, an activation energy of ∼274 kJ/mole is obtained.