抄録
Metal matrix composites (MMCs) are generally considered attractive as structural materials because of their superiority over polymer matrix composites (PMCs) for high-temperature application as well as their specific strength and modulus. It has been the most important and urgent problem to characterize the damage tolerance behavior for a wide use of advanced MMCs for primary aerospace and automotive structural applications. In this paper, fatigue crack growth tests were conducted on silicon-carbide-whisker-reinforced high-strength aluminium alloy matrix composite SiCw/2025 Al over a wide range of fatigue crack growth rates covering the threshold stress intensity factor range ΔKth. The effects of whisker orientation and stress ratio on the fatigue crack growth characteristics were investigated on the basis of fracture mechanics and fractography. The whisker reinforcements of the high strength 2025 Al alloy are found to be effective in improving the fatigue crack growth resistance, especially in the near-threshold stress intensity factor range.
