Squeeze Cast Metal Matrix Composites: Evaluation of Their Strength, Damping Capacity and Corrosion Resistance

Abstract

Several graphite fiber reinforced (planar random) metal matrix composites employing copper, aluminum, tin and babbitt matrices were fabricated by a newly devel oped high-pressure squeeze casting method. The fiber volume fraction of these composites ranged from 5 to 55%. These composites had relatively weak fiber-to-matrix bonding because of the near-absence of interfacial reaction between fiber and matrix materials. The tensile strength of these composites increased with fiber volume fraction up to about 25% followed by a gradual decrease for higher fiber volume fractions. Experiments were designed to evaluate various mechanical and physical properties of high pressure squeeze cast composites including the damping capacity and corrosion re sistance. Measurements of logarithmic decrement values at reasonant frequencies on can tilevered beam specimens have demonstrated that the damping capacity of the composites is much superior to that of wrought 6061-T6 Al and mechanically alloyed aluminum. Results on corrosion resistance of the composites in distilled water and 3.5% NaCl solu tion over a range of voltages and temperatures are presented and discussed.