Multi-response optimization of processing variants to fabricate graphene reinforced Al 2124 metal matrix composite using friction stir processing

Abstract

The development in metal matrix composites (MMCs) using nanomaterials has propelled quite a significant amount leading to diverse applications. Al 2124 alloy/composites have applications in aerospace engineering, since physical and mechanical properties are of primary importance. Recently Al 2124/20 vol% B4C (AMC220bc) have been introduced in the market supplied by AMC (Aerospace Metal Composites) processed through powder metallurgy. Foreseeing the applications of Al 2124 MMCs, research is needed to look into the properties of Al 2124-reinforced graphene (GNP) fabricated by friction stir processing (FSP). Processing parameters in FSP are significantly important that dictate the end properties of MMCs. Graphene-reinforced Al 2124 has been produced acquiring processing parameters consisting of tool rotation speed, tool transverse speed and plunge depth at constant groove width, and tool geometry by using Taguchi L9 orthogonal array. Optimization was performed using desirability functional analysis (DFA) by accounting for multi-characteristic performances consisting of density and hardness. From this research, optimum parameters were identified considering the peak value of composite desirability (dG) through DFA. Taguchi analysis showed that tool rotation speed has a strong influence compared to tool transverse speed and plunge depth. Results from analysis of variance (ANOVA) showed that tool rotation speed contributes majorly compared with other factors. Optical microscopy and scanning electron microscopy (SEM) were also conducted for the confirmation test, where it was seen that GNPs (in the form of stacked fragmented clusters) were homogeneously dispersed in the Al 2124 metal matrix, provided that all composites were free from defects.