Defect-based probabilistic fatigue life estimation model for an additively manufactured aluminum alloy

A review on isothermal rotating bending fatigue failure: Microstructural and lifetime modeling of wrought and additive manufactured alloys

“…Awd et al 115 demonstrated that increased porosity in Scalmalloy generated by DED techniques caused a 30% decrease in fatigue strength compared to LPBF‐processed material. Moreover, modeling of fatigue by Haridas et al 116 in AM Al–Cu–Mg–Zr showed that the amount and size of porosity strongly influenced the fatigue life, with a distribution of larger irregular‐shaped porosities decreasing component lifetime. AM‐induced keyhole porosity, if present, could also create potential challenges for high‐temperature alloys containing volatile Mg, Zn, and/or Mn, whose vaporizations are expected to increase the tendency for keyholing 113 …”

“…AM‐induced keyhole porosity, if present, could also create potential challenges for high‐temperature alloys containing volatile Mg, Zn, and/or Mn, whose vaporizations are expected to increase the tendency for keyholing 113 Inadequate solidification of metal powder can lead to the creation of agglomerates, which can become stress raisers that cause fatigue cracks 116 When the common strain localizing features such as porosity is eliminated by post‐processing treatments such as hot isostatic pressing, other microstructural defect precursors that form during cyclic loading of AM'd alloys, such as persistent slip bands, are predicted to initiate fatigue cracks 112 …”

“…113 • Inadequate solidification of metal powder can lead to the creation of agglomerates, which can become stress raisers that cause fatigue cracks. 116 • When the common strain localizing features such as porosity is eliminated by post-processing treatments such as hot isostatic pressing, other microstructural defect precursors that form during cyclic loading of AM'd alloys, such as persistent slip bands, are predicted to initiate fatigue cracks. 112 Even though we do not know much about IT-RBF of AM'd metals, Figure 21, developed by the authors, may schematically show the contributing factors to the IT-RBF failure in AM'd materials.…”

Recent developments and future trends in fatigue life assessment of additively manufactured metals with particular emphasis on machine learning modeling

“…Different AM processes will lead to different microstructures in materials, which play a key role in fatigue properties. Some microstructure-based models have been developed, in which crack initiation from a grain or an inclusion 214,215 and crack initiation due to dislocations 216 are considered.…”

“…In the work of Haridas et al, 214,215 a microstructurebased fatigue life prediction model for AM aluminum alloy was developed, in which the grain size, the friction stress of dislocation, the slip band, the inclusion size, and some microscopic energy parameters were all involved in. Additionally, a thorough statistical analysis has been performed on the size distribution of grains, pores, and inclusions.…”