Dynamic recrystallization and texture evolution of a novel near-α Ti–6Al–1Mo–2Zr-0.55Fe-0.1B alloy during hot compression
Liang Yang, S B Yu, Chao Zhan, Yujie Xia, Feng Liang, Feng Li, Hui Chang
Abstract
In this study, a new near-α titanium alloy of Ti–6Al–1Mo–2Zr-0.55Fe-0.1B, was investigated in terms of its flow behavior, microstructure evolution, dynamic recrystallization (DRX) mechanism and texture evolution during hot compression. The research focused primarily on the α+β phase region under varying deformation temperatures and strain rates. Variations in deformation temperature induced significant morphological changes, including the fragmentation, migration, and spheroidization of the original lamellar α phase. Correspondingly, the orientation of the deformed α grains evolved from < 1 ‾ 2 1 ‾ 0> to <0001> ∥ compression direction (CD), and the overall texture intensity weakened as the degree of DRX increased. A pronounced necklace structure was formed at high temperatures, with discontinuous dynamic recrystallization serving as the dominant softening mechanism. At high strain rates, the fraction of low-angle grain boundaries was increased, forming a fine-grained structure with a minimum average grain size of 1.15 μm. Orientation-dependent dislocation accumulation promoted the preferential alignment of DRX grains along CD ∥ < 1 ‾ 2 1 ‾ 0>. The localized high-strain regions facilitated the continuous nucleation and growth of new grains, enhancing the continuous dynamic recrystallization process. Based on the analysis of Schmid factor and pole figures, with increasing temperature, the contribution of basal <a> slip was gradually weakened, while the activation of prismatic slip was significantly enhanced. Moreover, under high-strain-rate conditions, pyramidal <c+a> slip played an auxiliary role in deformation coordination, resulting in a deformation mechanism dominated by multiple active slip systems.