POWDER METALLURGY PROCESSING OF ALUMINIUM MATRIX COMPOSITES WITH VERY HIGH VOLUME FRACTION OF SILICON CARBIDE REINFORCEMENT

摘要

Aluminium Metal Matrix Composites containing very high volume fractions of Silicon carbide have a unique set of properties that are ideally suited for the thermal management applications of electronic industry. The matching coefficient of thermal expansion (CTE) value of Al / 60-70 percent SiC with that of the Ga As and Si devices make them potential material for these applications. Conventionally these packages are made by melt infiltration technique. In the present study, powder metallurgical route using Vacuum Hot Pressing (VHP) technique is employed to synthesize high volume fraction composites (2124 Al / 70 percent SiCp.). Size(36#, 220# and 600#) and proportion of the reinforcement particles were varied to make different MMCs like mono-modal, bi-modal and tri-modal composites. These composites were studied for their mechanical and physical properties like density, flexural strength etc. Structure property correlation has been drawn among these composites. Necessity of higher processing temperatures for finer reinforced composites, achievement of higher densification in multi modal composites over mono-modal composites and lowered and matching CTE are some of the salient observations of the present study.