Effect of electromagnetic field and mechanical milling in the synthesis of metal matrix Nano composite

Abstract

Ceramic nanometric SiC particles (n-SiCp) were reinforced in 7075 aluminium matrix to synthesize the metal matrix nano composites (MMNCs). The inclusion as well as uniform distribution of nano particles in aluminium matrix is a great challenge. To accomplish this, a new hybrid stir casting technique was used to fabricate the MMNCs. The uniform distribution of the reinforcement depends on good wettability of reinforcement with the metal matrix. Hence, to improve the wettability, 1 wt % micro Mg particles were mechanically milled with two different additions of n-SiCp with weight fractions 1% and 1.5 % and injected into the matrix melt with the assistance of argon gas. As-casted materials were peak aged for 12 hours at 135º C. Tensile tests, low speed impact test and hardness tests were used to investigate mechanical behaviour and found that composite reinforced with 1% SiC exhibited better mechanical properties. The mechanical properties of nano-composites are characterized by employing optical microscopy, scanning electron microscopy and X-ray diffractometer. This method remarkably facilitated a uniform dispersion of nano-SiC within the aluminium matrix as well as a refinement of grain size.