Hot Deformation Behavior and Microstructural Evolution of a TiB₂/Al-Zn-Mg-Cu-Zr Composite

In the present work, the hot deformation behavior and microstructural evolution of a TiB₂/Al-Zn-Mg-Cu-Zr composite were studied. Hot compression tests were conducted within a temperature range of 370 °C to 490 °C and a strain rate of 0.001 s^-1 to 10 s^-1. We established the Arrhenius constitutive equation with Zener-Hollomon parameters and processing maps and discussed the microstructural evolution during hot deformation. The results indicated that the safe processing parameter region falls within 370 °C-490 °C and 0.001 s^-1-0.025 s^-1. The influence of the strain rate on the safe processing range is more dominant than that of deformation temperature, which is primarily attributed to TiB₂. Dynamic softening is primarily governed by dynamic recovery (DRV). Small particles (η, Al₃Zr) can pin dislocations, promoting the rearrangement and annihilation of dislocations and facilitating DRV. Higher temperatures and lower strain rates facilitated dynamic recrystallization (DRX). Continuous dynamic recrystallization (CDRX) occurs near high-angle grain boundaries induced by strain-induced boundary migration (SIBM). TiB₂ and large second-phase particles generate high-density geometrically necessary dislocations (GNBs) during hot deformation, which serve as nucleation sites for discontinuous dynamic recrystallization (DDRX). This enhances dynamic softening and improves formability.