Simultaneously improving the tensile strength and ductility of the AlNp/Al composites by the particle's hierarchical structure with bimodal distribution and nano-network

Generally, metal matrix composites'with homogenous microstructure exhibit good performance in mechanical properties, however, the shortcomings of limited strengthening effect by homogenous distributed reinforcements have been shown up in recent studies. In this work, the effect of reinforcement particles' hierarchical structure with bimodal distribution and nano-network on tensile properties of the AlNp/Al composites has been studied. A novel AlNp/Al composite with hierarchical structure has been fabricated using the in-situ liquid-solid reaction and hot extrusion, in order to further improve the mechanical properties. Furthermore, the AlNp/Al composite was processed by rotary swaging (RS) to obtain a more uniform structure. The results show that the AlNp/Al composites with hierarchical microstructure exhibit a superior ultimate tensile strength of similar to 410 MPa with uniform elongation of similar to 9.7%. However, the ultimate tensile strength and ductility of the AlNp/Al composite after swaging treatment decrease to 370 MPa and 6.7%, respectively. It can be concluded that the hierarchical structure has a distinct superiority in simultaneously improving the strength and ductility of the Al based composite over the homogenous structure. Furthermore, the strengthening and toughening mechanisms have been discussed as well.