2013 年 53 巻 2 号 p. 356-364
The recrystallization kinetics and microstructure evolution after unidirectional and multi-step cross rolling of interstitial free high strength steel has been investigated systematically. Microhardness, electron backscattered diffraction and X-ray diffraction was used to characterize the recrystallization kinetics, microstructure and texture evolution during annealing. The obtained experimental data on recrystallization was evaluated in terms of Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic model. The Avrami exponents varied between 1.03 at 1073 K to 1.4 at 948 K for unidirectionally rolled sample, while for cross rolling, it varied between 2.6 at 1073 K to 0.83 at 948 K. The recrystallization kinetics was observed to be faster for unidirectionally rolled samples. The deformed textures consisted of strong γ (ND//<111>) and α (RD//<110>) fibres in unidirectionally rolled sample, while a weak γ-fibre and strong rotated cube ({100}<110>) texture component was observed in cross rolled sample. After complete recrystallization, strong γ-fibre was observed in unidirectionally rolled sample, while strong γ and ε (TD//<110>) fibres were observed in cross rolled sample. The formation of recrystallization texture in unidirectionally rolled sample was explained by oriented nucleation. In cross rolled samples, orientation pinning and selective growth have a very strong role to play in developing the recrystallization textures.
