Increasing the ductility of heat-resistant AlNp/Al composites by submicron Al2O3 particles

Abstract

To improve the ductility of heat-resistant AlNp/Al composites, a strategy of hybrid particles with bimodal size distribution has been fabricated in this work. A series of hybrid Al matrix composites reinforced by nano AlN and submicron Al2O3 particles have been fabricated by liquid-solid reaction method and subsequent extrusion process. The effects of the submicron Al2O3 particles on the microstructure and tensile mechanical properties of the composites have been studied. Both nano AlN and submicron Al2O3 particles distributed homogeneously and well bonded with the Al matrix. Meanwhile, with the increase of the Al2O3 particles content, the ductility of (AlN + Al2O3)p/Al composites increased significantly without obvious sacrifice of ultimate tensile strength, and therefore a (AlN + Al2O3)p/Al composite with well-balanced strength and ductility was obtained. The ultimate tensile strength of (8.2AlN + 4Al2O3)p/Al composite at room temperature and high temperature (350 °C) can be up to 385 MPa and 150 MPa, and the total elongation can reach 14.6% and 5.0%, respectively. The strengthening and toughening mechanisms also have been discussed in detail.