The high temperature high cycle fatigue behaviour of a directionally solidified Co-base superalloy was investigated. The alloy has saperior fatigue resistance at 900℃ and its fatigue strength is up to 295MPa. Its σ-Nf curve is characterized by three distinct zones. The stronger dependence of Nf on or in the high .and low stress zones results from multiple fatigue crock initiation sites produced by high stress and oxidation effect in a prolonged exposure, respectively.
展开▼
