Preparation and mechanical properties of in situ Al2O3/Al composites by adding NH4AlO(OH)HCO3

Aluminium matrix composite reinforced by Al2O3 particles was produced by adding NH4AlO(OH)HCO3 into molten aluminum. The mechanical properties and wear behavior of the as-fabricated composites were studied. The results show that during stirring γ-Al2O3 particles were formed via decomposition reaction of NH4AlO(OH)HCO3, and the distribution of Al2O3 particles is more uniform in the matrix aluminum than directly added Al2O3 into molten aluminum. The density and the hardness values of the as-fabricated composites increase with increasing the particle volume fraction, while the tensile strength of the composites decreases with increasing the volume fraction of the Al2O3 particles. The wear rate of the composites decreases with increasing the volume fraction of the particle and loading. The in situ formed Al2O3/Al composite by adding NH4AlO(OH)HCO3 shows more superior mechanical and wear behaviors than that prepared by directly adding Al2O3 particles.