RECRYSTALLIZATION OF UNIDIRECTIONALLY SOLIDIFIED NI3AL DEFORMED IN TENSION

Behaviour and mechanisms of recrystallization at grain boundaries were investigated on stoichiometric Ni3Al which was unidirectionally solidified by a floating zone method. Two specimens were deformed in tension to the two strains of about 0, 17 and 0.28, and then were annealed at 1173 K for 3.6 x 10(3) s and 7.2 x 10(3), respectively. Recrystallized grains were formed by two kinds of mechanisms preferentially along the grain boundaries. The strain induced boundary migration (SIBM) mechanism can operated where dislocations with edge components impinged and piled up against the grain boundary. The other is the (111) rotation mechanism along the grain boundary where dislocations with screw components impinged and piled up. These results are similar to those in aluminum and copper, especially copper bicrystals.