Cyclic plastic material behavior of 316L manufactured by laser powder bed fusion (PBF-LB/M)

Johannes Diller, Lukas Rier, Dorina Siebert, Christina Radlbeck, Frank Krafft, Martin Mensinger

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

In laser powder bed fusion of metals (PBF-LB/M), the influence of laser parameters on the static mechanical properties is well known. Different laser parameters result in a higher or a lower tensile strength. Only little is known about the influence of the laser parameters on the cyclic plastic behavior at high strain amplitudes. Different laser parameters may result in a significant change in the stress levels during cyclic loading. In this study, the cyclic plastic material behavior at high strain amplitudes of up to 3.0% of AISI-316L manufactured by PBF-LB/M is investigated. Two different laser parameter sets are applied. One laser parameter set is outside the stable melting zone and the other one is inside the stable melting zone according to [1]. Metallographic analyses and static, as well as strain-controlled fatigue tests with a strain ratio of R = −1 were conducted. The plastic material behavior is dominated by softening, which is reduced with increasing strain amplitude due to mechanical twinning. Indeed, for strain amplitudes >2.5% twin-induced strain hardening is observed. A correlation between the twin-induced strain hardening behavior and the resulting maximum stress curve per endured cycle is observed. The laser parameters influence the generated stress level during cyclic plastic loading. It is shown, that the porosity highly affects the fatigue life in the low-cycle fatigue range. Finally, the strain-life curve is determined and approximated by the Manson-Coffin fatigue parameters.

Original languageEnglish
Article number112153
JournalMaterials Characterization
Volume191
DOIs
StatePublished - Sep 2022

Keywords

  • 316L
  • Laser powder bed fusion
  • Low-cycle fatigue
  • Strain-controlled fatigue testing
  • Strengthening mechanisms

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