Effect of Al₂O₃ on the Mechanical Properties of (B₄C + Al₂O₃)/Al Neutron Absorbing Materials

B₄C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel. In order to improve the high-temperature mechanical properties of B₄C/Al composites, in-situ nano-Al₂O₃ was introduced utilizing oxide on Al powder surface. In this study, the Al₂O₃ content was adjusted by utilizing spheroid Al powder with varying diameters, thereby investigating the impact of Al₂O₃ content on the tensile properties of (B₄C + Al₂O₃)/Al composites. It was found that the pinning effect of Al₂O₃ on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high temperature. As the result, with the increase in Al₂O₃ content and the decrease in grain size, the high-temperature strength of the composites increased significantly. The finest Al powder used in this investigation had a diameter of 1.4 μm, whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350 °C, surpassing that of traditional B₄C/Al composites.