Effects of hybrid reinforcements on flow softening of two-scale network-structured (TiBw+Ti₅Si₃)/TA15 composites during deformation in α+β region

In order to investigate the effects of reinforcements on the flow behavior of two-scale network-structured (TiBw + Ti₅Si₃)/TA15 composites, hot compression tests were conducted at temperatures ranging from 890 °C to 980 °C in α+β region, with strain rates varying from 1 s⁻¹ to 0.001 s⁻¹. The microstructure evolution and softening mechanisms during the hot deformation were analyzed. Results show that the primary α phase (α_p) first undergoes rotation and then globularization. The globularization processes of α_p include boundary splitting in thin lamella and continuous dynamic recrystallization (CDRX) in thick lamella. TiBw and Ti₅Si₃ promote the dynamic recovery (DRV) of β phase and globularization of the α_p by providing higher storage energy and nucleation sites. Deformation heat, DRV of β phase, rotation (in early stage) and globularization (in late stage) of α_p contribute to the flow softening. Additionally, the bending, fracture, and rotation of reinforcements along with their accelerated influence on matrix softening further promote flow softening.