Fatigue behavior of a thermally sprayed low carbon steel coating

The fatigue behavior of a thermally sprayed low carbon steel coating has been investigated at room and elevated temperatures. The coating was found to have higher fatigue resistance at 300°C than at room temperature. Further studies indicate that the higher fatigue resistance at the elevated temperature was related to a rapid increase in the elastic modulus of the coating with time during the early part of the fatigue life. The increase in the elastic modulus of the coating was shown to result from annealing of the as-sprayed microstructure at elevated temperatures. Following annealing, the weaker oxide-rich region of the microstructure also became more resistant to crack initiation. The strengthened oxide-rich region delayed accumulation of fatigue damage in the coating, leading to improved fatigue resistance of the coating at elevated temperatures.