Role of defects and microstructure on the fatigue durability of Inconel 718 obtained by additive layer manufacturing route

Cesar Moises Sanchez-Camargo, Yves Nadot, Jonathan Cormier, Fabien Lefebvre, Wen Hao Kan, Louis Ngai Sum Chiu, Chen Li, Aijun Huang

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

A Laser Powder Bed Fusion Inconel 718 produced with intentionally non-optimized parameters is investigated to understand the role of defects and microstructure on the high-cycle fatigue life. Samples from three built directions and three heat treatments were used for fatigue tests at room and 650°C under (Formula presented.). Printing orientation has a minor effect on fatigue life at both temperatures. Most samples failed from lack of fusion defects, carefully analyzed by scanning electron microscope (SEM) observations. Surface defect leads to transgranular fracture surface, while subsurface initiation leads to crystallographic fracture surface. (Formula presented.) curves related to hot isostatic pressure condition shown that defects have higher influence at (Formula presented.) than at 650°C. Kitagawa diagrams are plotted for both temperatures to quantify the influence of defect size on fatigue limit. Natural cracks are observed at the surface in order to discuss the relative part of initiation life in the whole fatigue life.

Original languageEnglish
Pages (from-to)4678-4693
Number of pages16
JournalFatigue and Fracture of Engineering Materials and Structures
Volume46
Issue number12
DOIs
Publication statusPublished - Dec 2023

Keywords

  • additive manufacturing
  • heat treatment
  • high cycle fatigue
  • lack of fusion defect
  • microstructure

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