Hot Compression Testing of Metal Matrix Composites Produced through Powder Metallurgy

Powder metallurgy remains a promising route for the manufacturing of Metal Matrix Composites (MMCs) with desirable properties, in this paper an attempt has been made to manufacture MMCs through powder metallurgy route and compression testing was performed on the MMCs. The aluminum (99% pure aluminum) metal matrix composites with 15% volume fraction of SiC (green bonded 25m size) were produced through powder metallurgy technique. The mixture of composite powders with graphite binder was first cold pressed and then vacuum hot pressed to attain the required density. The green compacts were further sintered in vacuum atmosphere to produce MMCs. The specimens 20 mm diameter by 20 mm length were hot pressed for a range of temperatures (300 -5007C), strains (0.1 -0.5) and strain rates (0.0087 /s to 2.7 Is). The true stress-true strain curves were drawn for the different testing conditions. Strain rate sensitivity, power dissipation efficiency, and instability parameter were estimated and processing maps were developed for 0.1 and 0.5 strains for AiH5% SiC composites. The optimum working regions were identified and validated through microscopic examination.