Tensile properties and strengthening effects of 6061Al/12 wt%B4C composites reinforced with nano-Al2O3 particles

Aluminum matrix Boron carbide composites is an important thermal neutron shielding material. In order to prepare 12 wt% B4C/6061Al composite with higher mechanical properties by powder metallurgy method, the new composite reinforced by Nano-Al2O3 particles was fabricated by hot isostatic pressing in the semi-solid temperature range. The tensile properties and strengthening effects of the composite were investigated in this research. The tensile stress-strain curve of the composites was tested by material testing machine, and the microstructure and tensile fracture morphology of composites were analyzed by scanning electron microscopy (SEM) and transmission electron microscopes (TEM). The results indicated that the tensile strength of the composite was greatly improved by the addition of Nano-Al2O3, but the elongation decreased obviously. Nano-Al2O3 particles had seriously affected the microstructure and fracture morphology of the composite and lead to the more obvious brittle fracture characteristics. Strengthening mechanisms of Nano-Al2O3 particles reinforced 6061Al/B4C composite have been discussed, which reveals that grain boundary strengthening mainly plays the most important role.