Failure Analysis of Cracks of Fan Blade in an Aeroengine

The crack was occurred on the fan blade of aeroengine.Crack mode as well as failure reason were identified by the examination of failed blade appearance,analysis of fracture surface,inspection of blade tip,chemical composition analysis,hardness test and metallurgical structure analysis.Results indicated that the crack of fan blade was high cycle fatigue.Because of bad friction compatibility of NiC coating with titanium alloy fan blade,the serious friction between blade and NiC coating as a pivotal factor led to early fatigue fracture.Moreover,the fatigue crack was also influenced by stress concentration and vibration.Finally,the improved proposal was provided to avoiding analogous failure.