Development of Aluminum-based Hybrid Composites with Graphite Nanofibers/Alumina Short Fibers: Processing and Characterization

Abstract

In this study, aluminum-based hybrid composites were developed and characterized. Initially, a hybrid preform was fabricated using graphite nanofibers (GNFs) and alumina short fibers (Al₂O_3sf) with the total volume fraction of fiber at 10, 15, and 20%. The hybrid preforms were then infiltrated with aluminum alloy (A356), and the microstructure and mechanical properties of the hybrid composites were evaluated. The Taguchi approach to experimental design was used to identify those process parameters that had the largest effects on hardness and porosity of the preform. The amount of binder was found to have the largest effect on hardness; volume fraction of fiber affected porosity most significantly. Scanning electron microscopy observations indicated that alumina short fibers were well dispersed within the aluminum matrix. Although GNFs formed clusters in certain regions, their distribution within the short-fiber network was relatively good. The hardness of these composites was found to be higher than that of Al/Al₂O_3sf mono-composites; however, their tensile strength and compressive strength were reduced considerably. This is attributed to the presence of agglomerated GNFs, which may weaken load sharing between the Al matrix and Al₂O_3sf.

Keywords

hybrid preform Taguchi method aluminum composites mechanical properties.

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