Nucleation and recrystallization kinetics in boron doped Ni76Al24 deformed to small strains

Nucleation and recrystallization behaviour of boron doped Ni76Al24 nickel aluminide, cold rolled upto small reductions of 25% has been examined at temperatures in the range of 850 to 925°C. Microstructural observations showed that nucleation and recrystallization occurred preferentially at grain boundaries, triple points and deformation bands. The presence of serrated grain boundaries in the microstructure, suggested strain induced grain boundary migration as a mechanism of nucleation and recrystallization. Using standard metallographic measurements, the average nucleation rates were calculated at a range of temperatures. As expected, the average nucleation rate increased with increasing temperature. The usual Arrhenious equation was used to determine activation energy of nucleation. The recrystallization kinetics were analysed using the Johnson-Mehl-Avrami relationship. The results have been found to be consistent with the recrystallization studies performed on ordered intermetallics.