EFFECTS OF ELECTROMAGNETIC FREQUENCY AND SIC NANOPARTICLES ON THE MICROSTRUCTURE REFINEMENT AND MECHANICAL PROPERTIES OF Al A357-1.5 WT% SIC NANOCOMPOSITES

In this research, the effects of electromagnetic stirring and 1.5 wt% SiC nanoparticles on the solidification microstructure and mechanical properties of alloy Al A357 were studied at three different frequencies (10, 35, and 60 Hz). The microstructural evolution was characterized by scanning electron and optical microscopy, and the mechanical properties were studied by hardness and room-temperature uniaxial tensile tests. The results showed that with an increase in frequency to 60 Hz in the presence of 1.5 wt% SiC nanoparticles, the dendrite size was reduced from 59.5 +/- 1.8 to 15.5 +/- 3.6 mu m (%73.9). By the application of electromagnetic stirrer frequencies from 0 to 60 Hz in the presence of 1.5 wt% SiC nanoparticles, the hardness, yield stress, and ultimate tensile stress of the Al A357-1.5 wt% SiC nanocomposites were increased by 30.9, 57.7, and 57.9%, respectively, compared to as-cast specimen. Orowan strengthening, Hall-Petch mechanism, and the load bearing were determined as the effective mechanisms in improvement in mechanical properties.