Abnormal grain growth in in situ TiB₂ particle-reinforced 7055 Al composites

Abnormal grain growth behaviors of in situ TiB₂ particle-reinforced Al composites under two-step annealing are investigated in this study. Abnormal grain growth occurs after first annealing at 300 °C for 10 h and second-step annealing at 450 °C for 3 min. High-energy grain boundaries with misorientation in the range of 20° ~ 45° are observed to promote grain boundary migration. Abnormally grown-up grains have typical orientation like P, Goss, Copper, {111} < 110 > , {111} < 112 > , and {112} < 110 > , which all own high-energy grain boundaries. TiB₂ particles are effective in pinning the migration of grain boundaries. The grain boundary energy has a greater impact on the abnormal grain growth than the pinning force of TiB₂ particles. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2021.