SYNTHESIS OF CAST METAL-MATRIX PARTICULATE COMPOSITES

The present review begins by briefly tracing history in the early days of development of cast metal-matrix composites and also outlines different casting routes for their synthesis. The problems faced by the quality of cast products and their relation to the process variables and characteristics of a given process, constitute the main theme of the review. The development of microstructure has been discussed in view of nucleation behaviour anticipated on the basis of estimated interface energies. The solidification around dispersoids and in regions away from it has been highlighted. Porosity in cast composites (its origin and control in cast components by suitable mould design) has engaged attention because of damage to mechanical properties due to porosity. The chemical reactions at the interface between dispersoid and matrix during processing of certain important systems of composites, have been described and the means of controlling these reactions have been indicated. The review concludes by drawing attention to the potential for application of cast composites in different industrial components and underlines the necessity of research in certain related fields so that industrial application of cast metal-matrix composites will soon become a reality.