Asian Journal of Chemistry Vol. 21, No. 10 (2009), S066-071 Al-Cu-Si - (Al 2 O 3 ) p composites using A 384.1 Al Alloys. NRIP J IT, ANAND K. TYAGI 1 and NIRMAL SINGH 2 SBS College of Engg. & Technology, Ferozpur. nripanu@gmail.com Al-Cu-Si (Al 2 O 3 ) p composite containing 5% Al 2 O 3 with particle size 0.220 μm were fabricated by modified stir casting technique. The addition of Al 2 O 3 in A.384.1, Al Alloy was found to increase hardness, proof stress and ultimate tensile strength. The fabricated composites showed higher peak hardness and lower peak ageing time as compared to the unreinforced Al alloy. In addition, ageing is found to increase the strength, micro and macro-hardness of the fabricated composites. The reinforced composite samples with different particle sizes of Al 2 O 3 i.e. 0.220, 0.106 and 0.053 μm were also fabricated to further investigate the interfacial characteristics. It is observed that the samples with small particle size exhibited clustering, whereas, the larger particles were found to mix up homogeneously in Al alloy matrix. Key Words: Al Alloys, composites, ageing, X-ray diffraction. INTRODUCTION Composite materials are designed and manufactured to have physical and mechanical properties suitable for the engineering applications. As compared to un-reinforced alloys, the reinforced materials are generally brittle and have a small elongation to tensile failure and low fracture toughness 1-2 . However, Al/Al alloy based ceramic particulate composites exhibit relatively promising characteristics as compared to others. Although there are a few reports on Al/Al alloys based MgO, SiC and Al 2 O 3 composites in recent years 3 , but as a whole these composites have been rarely investigated and thus received relatively limited attention. A number of methods have been reported in literature for fabricating these alloy composites 3 but due to high cost of manufacturing many of them have limited use 4 . Melt stir casting technique is the simplest and most economical fabrication method for these materials. In earlier studies, stirring of the melt has been done in open air 4 or using a furnace having provision to create an inert environment 3-4 . A simple modification of the conventional technique as proposed by Surappa & Rohatgi 3 leads to remarkable improvement in this method. Besides the other components required in the technique, we have an additional steel cover fitted with glass wool lining to make an inert atmosphere in order to prevent reaction of aluminum with environmental gases. 1 Shaheed Bhagat Singh College of Engineering & Technology, Ferozepur, akt@aol.in 2 Beant College of Engineering & Technology, Gurdaspur, nirmalsingh63@yahoo.com