Corrosion Fatigue Fracture Behavior of a SiC Whisker/Al Matrix Composite under Combined Tension-Torsion Loading

摘要

The corrosion fatigue strength of both the matrix and the composite was less in a 3.5% NaCl solution than in air. In the 3.5% NaCl solution, the corrosion fatigue strength of both materials was determined by the maximum principal stress, irrespective of the combined stress ratio. In the case of the matrix material, the crack initiation occurred by a brittle facet normal to the principal stress due to hydrogen embrittlement. However, in the composite material, the crack was initiated at a corrosion pit formed on the specimen surface. The dominating factor, which determined crack initiation at a pit, was the Mode Ⅰ stress intensity factor obtained by assuming the pit to be a sharp crack.