Experimental Investigation on Silicon Carbide Reinforced Duralumin based MMC Produced by Cold Compacting

Abstract

In the present investigation, an attempt is made to fabricate the Duralumin(DA) based Silicon Carbide (SiCp-6 and 12% wt.) reinforced composite by cold compacting the ball milled powders. The mechanically mixed powders taken into the die cavity are applied with a steady axial load in the range 22-30 T to produce the cylindrical compacts. The compacts are further subjected to sintering by holding it at a constant temperature of 5800C in Muffle furnace for 5 h and allowed to cool in the same for 18 h. The hardness of sintered composite is found to have improved as compared to the sintered duralumin compact prepared under similar process conditions. The SEM images showed the uniform distribution of the reinforcements in the matrix and the elemental composition is confirmed by the EDAX spectrum. The sintered specimens were further subjected to age hardening heat treatment. Specimens were soaked at 5500C for 2 h followed by water quenching at room temperature. The quenched specimens were artificially aged in the furnace at temperatures of 100, 150, and 2000C for various durations of time. The peak hardness obtained because of aging heat treatment is found to be much better than the corresponding sintered compacts. Compacts peak aged at 1000C exhibited better tensile strength than the other category of specimens. The composites developed in the present study would be most suitable in the applications requiring high strength and resistance to heat and wear.