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Thermo-mechanical fatigue behavior and crystal plasticity modelling of an additively manufactured nickel-based superalloy
  • +6
  • Lu Zhang,
  • Liujun Lu,
  • Y. Z. Wang,
  • Weilong Li,
  • Z. W. Yu,
  • Xingling Luo,
  • Rong Jiang,
  • Liguo Zhao,
  • Yingdong Song
Lu Zhang
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering

Corresponding Author:luzhang@nuaa.edu.cn

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Liujun Lu
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Y. Z. Wang
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Weilong Li
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Z. W. Yu
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Xingling Luo
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Rong Jiang
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Liguo Zhao
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Yingdong Song
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Abstract

Thermo-mechanical fatigue (TMF) tests were performed for vertically and horizontally selective-laser-melting (SLM) additively manufactured nickel-based superalloy, and also wrought superalloy for comparison. A mechanical strain amplitude of 0.8% was applied over a temperature range of 350-650℃. SLM samples in different printing directions exhibit notable disparities in cyclic hardening and softening, as well as average stress behaviour. Horizontally printed samples exhibit superior fatigue life under out-of-phase (OP) conditions compared to in-phase (IP) conditions. Compared to wrought samples, additively manufactured samples exhibit longer lifetimes under both IP and OP TMF conditions, but exhibit weaker performance during isothermal fatigue testing. Meanwhile, SEM analysis indicates that defects between layers have a greater impact on lifespan than intralayer defects. EBSD analysis reveals the crucial influence of microstructure on the fatigue performance of the samples. Despite having higher residual stress, horizontally printed samples exhibit longer fatigue life due to their finer grain size. The crystal plasticity finite element (CPFE) model was established to simulate the TMF cyclic deformation behaviour. The asymmetry of cyclic response was well captured, as well as the hardening-softening behaviour. Furthermore, thermo-mechanical loading was applied to a 2D model directly generated from EBSD based on this model.