Influence of oxidation of i -AlCuFeB particles on the formation of Al-based composites prepared by solid state sintering

We present new results concerning the formation of Al-based composites reinforced by icosahedral i-Al59Cu25.5Fe12.5B3 quasicrystalline particles. The issue is to limit the diffusion of Al from the matrix to the quasicrystalline particles during sintering in order to overcome the transformation of the i-phase into the omega-Al7Cu2Fe tetragonal phase. Here we have investigated the influence of an oxidation pre-treatment of the quasicrystalline particles onto the kinetics of this phase transformation by high energy X-ray diffraction. The quasicrystalline particles were annealed either in vacuum or in air, leading to a different thickness of the oxide layer. We show that the oxide barrier efficiently reduces the kinetics of Al diffusion, enabling the formation of composite materials with no phase transformation during the sintering process. The dependence of the tribological properties of these composites is investigated as a function of the volume fraction of i-AlCuFeB particles.