Fabrication and properties of graphite fiber reinforced magnesium

Graphite fiber reinforced magnesium composites have been fabricated by infiltration and liquid phase hot pressing techniques. Although pure magnesium does not wet graphite, weting and bonding were achieved by precoating the graphite fibers with titanium. Tensile strengths and elastic moduli of flat rectangular composite specimens were measured and compared with Rule of Mixtures strengths. Significant strengthening and stiffening were achieved. Tensile strength was increased by 170 pct and the elastic modulus by 100 pct. Measured elastic moduli were in good agreement with Rule of Mixtures values. The highest tensile strength was about 83 pct of the Rule of Mixtures strength. It is believed that specimen porosity and fiber misalignment account for the bulk of this difference and that an improved fabrication technique will yield specimens with higher strengths. Fracture modes are presented and discussed.