SIC/Al 4C 3 interfaces in aluminum—silicon carbide composites : Carim, A.H. Mater itLett Oct. 1991 12 (3) 153–157

Abstract

Aluminum MMCs are preferred to other conventional materials in the fields of aerospace, automotive and marine applications owing to their improved properties like high strength to weight ratio, good wear resistance etc. In the present work an attempt has been made to synthesize metal matrix composite using 7075Al as matrix material reinforced with ceramic Al4C3 particulates using liquid metallurgy route in particular stir casting technique. The addition level of reinforcement is being varied from 2 - 10wt% in steps of 2wt%. For each composite, reinforcement particles were preheated to a temperature of 200°C and then dispersed in steps of three into the vortex of molten Al7075 alloy to improve wettability and distribution. Microstructural characterization was carried out for the above prepared composites by taking specimens from central portion of the casting to ensure homogeneous distribution of particles. Hardness and tensile strength of the prepared composite were determined before and after addition of Al4C3 particulates to note the extent of improvement. Microstructural characterization of the composites has revealed fairly uniform distribution and some amount of grain refinement in the specimens. Further, the hardness and tensile strength are higher in case of composites when compared to unreinforced 7075Al matrix, also increasing addition level of reinforcement has resulted in further increase in both hardness and tensile strength.