# Fabrication of Graphite Flake/Al Composites via the Hybrid Powder-Melt Process: Synergistic Enhancement of Strength and Conductivity Through Low Content Addition

## TL;DR

This paper introduces a new method to make aluminum composites with graphite flakes that significantly boost strength and conductivity.

## Contribution

A hybrid powder-melt process is proposed to enhance both strength and conductivity in aluminum composites with low graphite flake content.

## Key findings

- A 0.2 wt.% graphite flake composite achieved 100.9 MPa tensile strength and 67.1% IACS conductivity.
- Low graphite flake content suppressed electron scattering via semi-coherent interfaces.
- Higher flake content caused conductivity and plasticity decline due to Al4C3 phase, grain boundary scattering, and porosity.

## Abstract

This study addresses the challenge of simultaneously improving the electrical conductivity and strength of aluminum alloys. We innovatively combine powder metallurgy with melt stirring casting to fabricate graphite flake-added aluminum matrix composites through secondary remelting, electromagnetic stirring, and extruding. The influence of graphite flake content gradient (0–3.0 wt.%) on the mechanical properties and electrical conductivity was systematically investigated. Our results demonstrate that the composite with 0.2 wt.% graphite flakes (sample GM02) exhibits optimal comprehensive performance: tensile strength reaches 100.9 MPa (a 124% increase over pure Al), and electrical conductivity reaches 67.1% IACS (a 9.6% increase). Microstructural analysis reveals that low-content graphite flakes effectively suppressed electron scattering by forming semi-coherent interfaces. However, when graphite flake content exceeds 0.5 wt.%, a significant decrease in conductivity and plasticity (elongation below 10%) occurs due to increased Al4C3 phase formation, enhanced grain boundary scattering caused by grain refinement, and porosity defects induced by graphite flake agglomeration. This study provides a novel approach for the industrial production of high-performance, lightweight conductive components.