Low Cycle Fatigue Behavior of AZ91D Magnesium Alloy Containing Rare-Earth Ce Element

AbstractLow cycle fatigue test of AZ91D+0.3%Ce alloy was carried out in tension-compression symmetric cycle at room temperature, with triangular waveform-loading frequence in 1Hz and equivalent strain amplitude varied from 0.2% to 1.2% .The fatigue fracture morphology of the alloy was observed by SEM. The results indicate that the σ-ɛ hysteresis loops of AZ91D+0.3%Ce magnesium alloy exhibit some behaviors such as inflexion, asymmetry of tension and compression and serrated flow deformation at the higher total strain amplitudes; Fatigue life of AZ91D+Ce alloy is decreased with the increase of the equivalent strain amplitude, confirming to the equation of the Manson-Coffin;The behaviors of cyclic stress response and stress-strain of magnesium alloy mainly show cyclic strain hardening; Fatigue fracture of all the magnesium alloys exists several fatigue source zones, as the strain amplitude increases, the fracture surface becomes more rough and concavo-convex