Effect of dynamic recrystallization on texture orientation and grain refinement of Ti6Al4V titanium alloy subjected to laser shock peening

• Published in: Journal of alloys and compounds 2021-01, Vol.850, p.156672, Article 156672
• Main Authors: Pan, Xinlei, Wang, Xuede, Tian, Zeng, He, Weifeng, Shi, Xiaosong, Chen, Peiming, Zhou, Liucheng
• Format: Article
• Language: English
• Subjects: Deformation; Dynamic recrystallization; Edge dislocations; Electron backscatter diffraction; Grain refinement; High strain rate; Laser shock peening; Laser shock processing; Misalignment; Nucleation; Orientation; Peening; Recrystallization; Shear bands; Slip; Texture; Titanium alloy; Titanium alloys; Titanium base alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156672

In this paper, using electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) characterization, we systematically investigated the dynamic recrystallization (DRX) mechanism and its effects on the texture orientation and grain refinement of Ti6Al4V titanium alloy subjected to laser shock peening (LSP). The results indicated shear bands-induced DRX mechanism played a vital role in texture transition and grain refinement during LSP. Based on the observation, the DRX mechanism was determined as continuous dynamic recrystallization (CDRX). Due to the wide range of local misorientation of grains within shear bands, the new dynamic recrystallized grains exhibited preferred selection of [1−21−0] orientation, thereby resulting in the original [011−0] fiber component weakening. The deformation is mainly supported by basal slip and pyramidal slip in α phase during LSP, activating massive non-basal dislocation for the subsequent CDRX process. The more nucleation sites available closer to the surface, as well as the increasing adiabatic temperature induced by ultra-high strain rate deformation there, contributed to the improved DRX, resulting in more intense grain refinement on the top surface. •Continuous dynamic recrystallization occurred during laser shock peening.•The new dynamic recrystallized grains with a wider crystal crystallographic orientation nucleate from shear bands.•The dynamic recrystallization process was mainly supported by basal slip and pyramidal slip.•The finer grains are formed on the surface by dynamic recrystallization.