Tensile property and fracture mechanism of a neutron absorbing B4Cp/Al composite at elevated temperatures

Abstract

In this study, the effects of strain rate and thermal exposure time on the mechanical properties of an annealed B4C particle-reinforced 6061Al matrix composite at various elevated temperatures were investigated, and the failure mechanism caused by the tensile temperature and strain rate was elucidated. At constant tensile temperature, an increase in the strain rate from 10−3 to 10−1 s−1 resulted in an increase in the ultimate tensile strength and a decrease in the ductility of the annealed composite. For the same strain rate, when the tensile temperature increased from 373 to 573 K, the ultimate tensile strength of the annealed composite decreased, although the ductility increased. With increasing thermal exposure time, the composite possessed good thermal stability, which was due to reduced dislocation density in the composite because of the annealing treatment. Regardless of the tensile temperature and strain rate, the fracture mechanism of the composite at elevated temperatures included matrix ductile fracture and a small amount of interface debonding between the B4C particles and matrix. This study offers a reference for the service safety of B4Cp/Al composites with structural and functional characteristics.