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

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:797

Article

Deng, Dunyong¹  Peng, Ru Lin¹  Moverare, Johan¹ 

[1] Linkoping Univ, Dept Management & Engn, Div Engn Mat, SE-58183 Linkoping, Sweden

关键词: IN718;    Selective laser melting (SLM);    Electron beam melting (EBM);    Forged;    Dwell;    Fatigue;    Creep;    Environmentally assisted grain boundary attack;    Crack propagation;   

DOI  :  10.1016/j.msea.2020.140072

来源: Elsevier

【 摘 要 】

The dwell-fatigue responses of high temperature materials, such as IN718, manufactured via additive manufacturing processes with different microstructures is of practical interest in terms of time-dependent cracking resistance at elevated temperature. In the present study, the dwell-fatigue cracking behaviours of IN718 manufactured via selective laser melting (SLM) with different heat treatments, and via electron beam melting (EBM) with different scanning strategies were compared at 550 degrees C and with a long 2160 s dwell-holding period. Comparison has also been made with a conventional forged counterpart. 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 proposed. In addition, the effects of other microstructure features on the dwell cracking resistance are also discussed.

【 授权许可】

Free