Ceramic matrix composites reinforced with metallic particles exhibit good mechanical properties. One research line has involved the fabrication of 3A (alumina-aluminide alloys) composites via in situ consolidation of aluminum reactive powders mixed with a metallic oxide. In this paper the solid state reactions for the Al-MoO3 system and the effect of the precursor compositions for obtaining Al2O3 composites and intermetallic aluminides are studied. The reactions in vacuum for the 25°C to 750°C temperature range, and the microstructural evolution up to 1200°C were studied. DTA-TG and DSC were used to determine that a heating rate of 1°C/min at the critical range of 500-600°C, resulted in controlled aluminothermic reactions. XRD and SEM showed that in the sintered composites a microstructure composed of an Al2O3 matrix and a Mo aluminide/metallic Mo dispersed phase was present. The precursor composition affects the dispersed phase in the composite (Mo aluminides and/or metallic Mo), the relative Al2O3/second phase quantities, and the hardness of the composite sintered at 1450°C.
|Translated title of the contribution
|Solid state reactions in the Al-MoO3 system for the synthesis of Al2O3-Mo aluminide composites
|Number of pages
|Revista de Metalurgia (Madrid)
|Published - 2002