Further studies into crack growth in additively manufactured materials

Athanasios P. Iliopoulos, Rhys Jones*, John G. Michopoulos, Nam Phan, Calvin Rans

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

22 Citations (Scopus)
44 Downloads (Pure)


Understanding and characterizing crack growth is central to meeting the damage tolerance and durability requirements delineated in USAF Structures Bulletin EZ-SB-19-01 for the utilization of additive manufacturing (AM) in the sustainment of aging aircraft. In this context, the present paper discusses the effect of differentAMprocesses, different build directions, and the variability in the crack growth rates related to AM Ti-6Al-4V, AM Inconel 625, and AM 17-4 PH stainless steel. This study reveals that crack growth in these three AM materials can be captured using the Hartman-Schijve crack growth equation and that the variability in the various da/dN versus DK curves can be modeled by allowing the terms DKthr and A to vary. It is also shown that for the AM Ti-6AL-4V processes considered, the variability in the cyclic fracture toughness appears to be greatest for specimens manufactured using selective layer melting (SLM).

Original languageEnglish
Article number2223
Number of pages18
Issue number10
Publication statusPublished - 1 May 2020


  • Additive manufacture
  • Aircraft sustainment
  • Fatigue
  • MIL-STD-1530D
  • Structures Bulletin EZ-SB-19-01

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