Creep-fatigue properties and deformation mechanism of 316L steel fabricated by laser powder bed fusion (PBF-LB/M)

Yefeng Chen, Xiaowei Wang, Yuxin Jiang, Rongqing Dai, Dewen Zhou, Yong Jiang, Jochen Tenkamp, Alexander Koch, Jian Weng, Shengping Wu, Frank Walther, Jianming Gong

Research output: Contribution to journalArticlepeer-review

Abstract

To ensure the structural integrity of components manufactured by laser powder bed fusion method at extreme service condition, the creep-fatigue interaction (CFI) properties of PBF-LB/M materials need to be investigated. As a common structural material in nuclear plants, 316L stainless steel is chosen and fabricated to samples using PBF-LB/M method. A series of CFI tests at 550 °C are undertaken on PBF-LB/M 316L to investigate its deformation behavior and microstructural evolution, specifically focusing on the effects of varying tensile holding time on fatigue-creep competition mechanism. The creep voids formation, coarsen of cellular sub-structure, texture evolution and σ-phase formation are observed in PBF-LB/M 316L after cyclic deformation. PBF-LB/M 316L exhibits a fatigue life 35 % superior to that of traditional 316L under LCF loading. Nevertheless, with an increase in tensile holding time to 600 s, the fatigue life of PBF-LB/M 316L diminishes by 17 % compared to traditional 316L. The fatigue cracks induced by CFI tests are all initiated from lack-of-fusion defects at the sub-surface and propagate intergranularly.

Original languageEnglish
Article number146881
JournalMaterials Science and Engineering: A
Volume910
DOIs
StatePublished - Sep 2024

Keywords

  • Creep voids
  • Creep-fatigue interaction
  • Microstructure
  • PBF-LB/M
  • σ-phase

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