Formation and properties of Al composites reinforced by quasicrystalline AlCuFeB particles

Abstract

Al-based composites reinforced by icosahedral (i-) Al₅₉Cu_25.5Fe_12.5B₃ quasicrystalline particles were prepared by solid-state sintering. It was found that Al diffusion from the matrix to the quasicrystalline particles induces phase transformation into the ω-Al₇Cu₂Fe tetragonal phase. In order to preserve the i phase, we used an oxidation pre-treatment of the particles and studied its influence on the kinetics of the phase transformation (Al + i → ω) as a function of temperature by high energy X-ray diffraction. The oxide layer acts as a barrier, reducing efficiently the diffusion of Al up to a sintering temperature of 823 K, allowing the control of the phases in the composites. The mechanical properties and the friction behaviour of the composites were investigated and show the negative influence of the oxide on the interface strength.

Keywords:

• quasicrystals
• metal matrix composites
• phase transformation
• oxidation
• tribological properties
• compressive properties

Acknowledgements

We would like to thank the staff of the ID15B beamline at the European Synchrotron Radiation Facility for technical assistance. We are grateful to S. Raffy (St Gobain) for the provision of quasicrystalline powders and to P. Delcroix for preparing samples by cold isostatic pressing. Help in SEM and compression test experiments by D. Bonina (LSG2M, Nancy) and O. Ferry (LPM, Nancy) is greatly acknowledged. This work was supported by the ADEME agency under contract n° 03 66 033.