A comparison study of the dwell-fatigue behaviors of additive and conventional IN718: The role of dislocation substructure on the cracking behavior

Dunyong Deng, Ru Lin Peng, Johan Moverare

Linköping University, Sweden

The time-dependent cracking resistance of IN718, manufactured via additive manufacturing processes with different microstructures is of practical interest at elevated temperature. In the present study, the dwell-fatigue cracking behaviors of SLM, EBM and forged IN718 were compared at 550 °C and with a long 2160 s dwell-holding period. Detailed microstructure characterizations have been done to correlate the role of dislocation substructures on the dwell-fatigue damage mechanisms and cracking resistances. A mechanism regarding the susceptibility of the dislocation cell substructure in SLM materials to creep damage is also proposed.