Failure analysis and characterization of Cardan shaft's part under fully reversed torsional fatigue loading

Cardan shaft is a part of a vehicle that carries power from the engine to the wheels via rear differential and axle in rear wheel drive. Cardan shaft is performed fatigue tests for design verification, process verification and layout qualification. It is called "fully reversed sinusoidal accelerated fatigue test" which data are acquired from the vehicle during the service life. Investigation of cardan shaft's part after failure is important to prevent potential service failure and to improve the performance. In the scope of the thesis, characterization and failure analysis of the cardan shaft's part was performed so that the root cause of the fracture as a result of the fully reversed sinusoidal fatigue test. Cardan shaft, which was produced mass production condition, was performed fatigue test. Then, the raw material of fractured cardan shaft's part was investigated mechanically, chemically and metallographically. After that, the fractured cardan shaft's part was investigated mechanically and metallographically. And fractured surface of cardan shaft's part was characterised in scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS).