Crack Growth Characteristics ofAluminumAlloys Dominated by the Mechanisms of Fatigue Crack Growth or Stress Corrosion Cracking

Abstract

Crack growth characteristics were investigated under static and cyclic loading conditions for aluminum alloys in humid and dry air environments in order to clarify the dominating crack growth mechanisms, i.e. stress corrosion cracking (SCC) and fatigue crack growth (FCG). The frequencies of the cyclic loading varied between 0.02 Hz and 20 kHz using three types of testing machine including ultrasonic fatigue. Crack growth mechanisms were discussed based on the traditional model proposed by McEvily and Wei. The results revealed that the crack growth mechanisms were dominated by SCC at 0.02Hz, while they were dominated by FCG at 20Hz and 20kHz.