Synergistic improvement of strength and ductility in thermal-neutron absorption Al-Si-xGd alloys via cold rolling and annealing

To overcome the poor ductility and limited formability of conventional B 4 C-reinforced Al-based thermal-neutron absorption materials, processable Al-Si-Gd alloys with fracture elongations exceeding 15% were developed through cold rolling and annealing. Increasing Gd content transforms the second phases from spherical and rod-like Gd(AlSi) 2 into larger plate-like GdAlSi, accompanied by the formation of a core–shell Gd(AlSi) 2 @GdAlSi structure due to Gd segregation and sequential solidification. Cold rolling fragments coarse plate-like and core–shell particles and redistributes fine particles into clustered lamellar regions, effectively refining and homogenizing the microstructure. This microstructural regulation promotes load transfer and GND-induced dislocation hardening, while reducing stress concentration and delaying void evolution. This study provides a new strategy for designing Al-Si-Gd alloys with improved mechanical performance and effective thermal-neutron absorption capability.