Abstract
The threshold of effective stress intensity range ΔK eff th of aluminium alloy 6061 and a 16 vol.% and a 21 vol.% Al2O3-particle-reinforced aluminium alloy was investigated. In the near-threshold regime the fatigue crack propagates predominately in the aluminium matrix, but the effective threshold ΔK eff th increases with increasing particle content. The main reason for this increase in ΔK eff th is the reduction in the local crack driving force at the crack tip in the aluminium matrix due to increase in Young's modulus of the surrounding composite.
