Effects of Gd Addition on the Hot Deformation Behaviors of B₄C_p/Al6061 Neutron Absorber Composites

B₄C_p/Al6061 composites with and without Gd addition fabricated by ultrasound-assisted casting method were subjected to hot compression tests (temperature range: 653 K to 753 K; strain rates: 0.001 to 1 s⁻¹) with the aim of studying the effects of Gd on the hot deformation behaviors of the neutron absorber composites. Experimental results showed that the average grain size of composites could be effectively refined from 144 to 44 μm due to the addition of Gd. The added Gd also lead to the formation of Al₃Gd particles which mainly distributed along grain boundaries (GBs). The constitutive equations of the two composites were established and the apparent activation energy (Q) decreased from 183.3 to 175.8 kJ/mol after Gd addition, indicating that the deformation resistance was decreased with Gd addition. The hot processing maps of the two samples were established and the results declared that the safe region and the instability region were changed with Gd addition. Moreover, the microstructural evolutions of the two samples under various deformation conditions were investigated. The results indicated that the dynamic recrystallization (DRX) frictions of the two composites first increased and then decreased with decreasing temperature and increasing strain rate. Furthermore, Gd addition could promote DRX due to the particle stimulate nucleation (PSN) and finer grains. This research provided important guidance for the plastic deformation of the novel B₄C_p/Al6061 neutron absorber composites with Gd addition.