Mechanical spectroscopy of Mg reinforced with Al2O3 short fibers and C nanotubes

Magnesium matrix composites have been developed, in which the high damping magnesium matrix has been reinforced either with multi-wall carbon nanotubes or with Al2O3 SAFFIL short fibers (40–100 μm), the interface of which was modified by chemical vapor deposition of carbon nanotubes before their infiltration with magnesium. In this case, it was found that the addition of the carbon nanotubes increases the high temperature (500 K) shear modulus of the composite by about 20%. A thermal hysteresis is observable in the mechanical loss spectra, which may be associated with the transitory effects generally observed in the metal matrix composites. These transitory effects are strongly reduced when the reinforcements are carbon nanotubes only, because their small size generates smaller interface thermal stresses.