2002 Volume 43 Issue 9 Pages 2243-2248
The difference in mechanisms of microstructure formation between static and dynamic recrystallization in pure nickel was studied on the basis of texture and EBSP analyses. Uniaxial compression was conducted at room temperature, followed by annealing at 905 K from 10 s to 28.8 ks. The process of static, primary recrystallization was traced by optical microscopy and the measurement of micro-Vickers hardness. Fraction of statically recrystallized region was 30% and 80% at annealing for 10 s and 60 s, respectively. Annealing longer than 60 s results in a 100% recrystallized state. The value of maximum pole density of texture was 4.6 after the uniaxial compression up to the true strain of −0.66. During static recrystallization, the texture became weak and finally the maximum pole density fell off in 2.0. The position of maximum pole density, however, did not change from (011) (compression plane). At the early stage of static recrystallization, new grains nucleated with random orientation in the vicinity of grain boundaries, inhomogeneously deformed regions. On the other hand, at the later stage of static recrystallization, new grains formed from the regions suffered from relatively homogeneous deformation. At this stage, the main component of the texture was (011) though the texture itself was weak. In dynamic recrystallization, new grains nucleated with random orientation during the deformation giving high values of Zener-Hollomon parameter. It was concluded that, during dynamic recrystallization, the deformation proceeded and hence inhomogeneously deformed regions continuously formed in the vicinity of grain boundaries, resulting the preferential formation of new grains.
