Advertisement

Non-destructive characterization of process-induced defects and their effect on the fatigue behavior of austenitic steel 316L made by laser-powder bed fusion

  • Felix SternEmail author
  • Jochen Tenkamp
  • Frank Walther
Full Research Article
  • 49 Downloads

Abstract

Additive manufacturing (AM) offers a high potential for light weight applications due to its possibility to generate complex structures with a high freedom of design compared to conventional techniques. However, the mechanical characterization of additively manufactured materials has become an essential topic in research over the last years to use AM parts for structural components especially in the automotive and aerospace industry. In the current research, specimens for fatigue tests made of the austenitic stainless steel AISI 316L processed by laser-powder bed fusion technique with three different building orientations were investigated. The gauge sections of the fatigue specimens were scanned by microfocus computed tomography (µ-CT) to detect and identify process-induced defects. The 3D information about the defects gained by µ-CT were compared with the crack-initiating defect on the fractured surfaces. The fatigue data were used for a model-based description of the fatigue strength based on the √area-parameter model. The results depict that the fatigue life is significantly influenced by the orientation of the inherent pores caused by the building direction causing a significant scatter in fatigue life. The µ-CT data allow to estimate the fatigue strength using the √area-parameter model based on the identified critical defects and are in good accordance with the results from the fatigue tests and the data obtained by fractography. Additionally, it could be shown that the √area-parameter model is applicable for additively manufactured 316L steel. It can also give an explanation for the anisotropic fatigue behavior, which supports the assumption that mainly the orientation of the pores and their √area-parameter are influencing the fatigue strength.

Keywords

Additive manufacturing Austenitic steel Effects of defects Micro-computed tomography (µ-CT) √area-parameter model 

Notes

Acknowledgements

The authors would like to thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for its financial support within the research project “Mechanism-based assessment of the influence of powder production and process parameters on the microstructure and the deformation behavior of SLM-compacted C + N steels in air and in corrosive environments” (WA 1672/30-1).

Compliance with ethical standards

Conflict of interest

The authors declare no conflict of interest.

Supplementary material

40964_2019_105_MOESM1_ESM.docx (6.5 mb)
Supplementary material 1 (DOCX 6610 kb)

References

  1. 1.
    Günther J, Krewerth D, Lippmann T, Leuders S, Tröster T, Weidner A, Biermann H, Niendorf T (2017) Fatigue life of additively manufactured Ti–6Al–4V in the very high cycle fatigue regime. Int J Fatigue 94:236–245.  https://doi.org/10.1016/j.ijfatigue.2016.05.018 CrossRefGoogle Scholar
  2. 2.
    Tammas-Williams S, Withers PJ, Todd I, Prangnell PB (2017) The influence of porosity on fatigue crack initiation in additively manufactured titanium components. Sci Rep 7(1):7308.  https://doi.org/10.1038/s41598-017-06504-5 CrossRefGoogle Scholar
  3. 3.
    Aleshin NP, Grigor’ev MV, Shchipakov NA, Prilutskii MA, Murashov VV (2016) Applying nondestructive testing to quality control of additive manufactured parts. Russ J Nondestruct Test 52(10):600–609.  https://doi.org/10.1134/S1061830916100028 CrossRefGoogle Scholar
  4. 4.
    Siddique S, Imran M, Rauer M, Kaloudis M, Wycisk E, Emmelmann C, Walther F (2015) Computed tomography for characterization of fatigue performance of selective laser melted parts. Mater Des 83:661–669.  https://doi.org/10.1016/j.matdes.2015.06.063 CrossRefGoogle Scholar
  5. 5.
    Ziółkowski G, Chlebus E, Szymczyk P, Kurzac J (2014) Application of X-ray CT method for discontinuity and porosity detection in 316L stainless steel parts produced with SLM technology. Arch Civ Mech Eng 14(4):608–614.  https://doi.org/10.1016/j.acme.2014.02.003 CrossRefGoogle Scholar
  6. 6.
    Dewulf W, Tan Y, Kiekens K (2012) Sense and non-sense of beam hardening correction in CT metrology. CIRP Ann 61(1):495–498.  https://doi.org/10.1016/j.cirp.2012.03.013 CrossRefGoogle Scholar
  7. 7.
    Maskery I, Aboulkhair NT, Corfield MR, Tuck C, Clare AT, Leach RK, Wildman RD, Ashcroft IA, Hague RJM (2016) Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using X-ray computed tomography. Mater Charact 111:193–204.  https://doi.org/10.1016/j.matchar.2015.12.001 CrossRefGoogle Scholar
  8. 8.
    Yusuf S, Chen Y, Boardman R, Yang S, Gao N (2017) Investigation on porosity and microhardness of 316L stainless steel fabricated by selective laser melting. Metals 7(2):64.  https://doi.org/10.3390/met7020064 CrossRefGoogle Scholar
  9. 9.
    Ziółkowski G, Szymczyk P, Pawlak A, Kurzynowski T, Dybała B, Chlebus E (2017) Porosity detection by computed tomography. PAR 21(3):27–34.  https://doi.org/10.14313/PAR_225/27 CrossRefGoogle Scholar
  10. 10.
    Esposito F, Gatto A, Bassoli E, Denti L (2018) A study on the use of XCT and FEA to predict the elastic behavior of additively manufactured parts of cylindrical geometry. J Nondestruct Eval 37(4):1147.  https://doi.org/10.1007/s10921-018-0525-x CrossRefGoogle Scholar
  11. 11.
    Carlton HD, Haboub A, Gallegos GF, Parkinson DY, MacDowell AA (2016) Damage evolution and failure mechanisms in additively manufactured stainless steel. Mater Sci Eng, A 651:406–414.  https://doi.org/10.1016/j.msea.2015.10.073 CrossRefGoogle Scholar
  12. 12.
    Siddique S, Awd M, Tenkamp J, Walther F (2017) Development of a stochastic approach for fatigue life prediction of AlSi12 alloy processed by selective laser melting. Eng Fail Anal 79:34–50.  https://doi.org/10.1016/j.engfailanal.2017.03.015 CrossRefGoogle Scholar
  13. 13.
    Murakami Y (2002) Metal fatigue: effects of small defects and nonmetallic inclusions, 1st edn. Elsevier, AmsterdamGoogle Scholar
  14. 14.
    Blinn B, Ley M, Buschhorn N, Teutsch R, Beck T (2019) Investigation of the anisotropic fatigue behavior of additively manufactured structures made of AISI 316L with short-time procedures PhyBaLLIT and PhyBaLCHT. Int J Fatigue 124:389–399.  https://doi.org/10.1016/j.ijfatigue.2019.03.022 CrossRefGoogle Scholar
  15. 15.
    Biswal R, Zhang X, Shamir M, Al Mamun A, Awd M, Walther F, Khadar Syed A (2019) Interrupted fatigue testing with periodic tomography to monitor porosity defects in wire + arc additive manufactured Ti–6Al–4V. Addit Manuf 28:517–527.  https://doi.org/10.1016/j.addma.2019.04.026 CrossRefGoogle Scholar
  16. 16.
    Romano S, Brandão A, Gumpinger J, Gschweitl M, Beretta S (2017) Qualification of AM parts: extreme value statistics applied to tomographic measurements. Mater Des 131:32–48.  https://doi.org/10.1016/j.matdes.2017.05.091 CrossRefGoogle Scholar
  17. 17.
    Stern F, Kleinhorst J, Tenkamp J, Walther F (2019) Investigation of the anisotropic cyclic damage behavior of selective laser melted AISI 316L stainless steel. Fatigue Fract Eng Mater Struct 42(11):2422–2430.  https://doi.org/10.1111/ffe.13029 CrossRefGoogle Scholar
  18. 18.
    Awd M, Stern F, Kampmann A, Kotzem D, Tenkamp J, Walther F (2018) Microstructural characterization of the anisotropy and cyclic deformation behavior of selective laser melted AlSi10Mg structures. Metals 8(10):825.  https://doi.org/10.3390/met8100825 CrossRefGoogle Scholar
  19. 19.
    Kempen K, Thijs L, van Humbeeck J, Kruth J-P (2012) Mechanical properties of AlSi10Mg produced by selective laser melting. Phys Proc 39:439–446.  https://doi.org/10.1016/j.phpro.2012.10.059 CrossRefGoogle Scholar
  20. 20.
    Thijs L, Kempen K, Kruth J-P, van Humbeeck J (2013) Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder. Acta Mater 61(5):1809–1819.  https://doi.org/10.1016/j.actamat.2012.11.052 CrossRefGoogle Scholar
  21. 21.
    Attar H, Bönisch M, Calin M, Zhang L-C, Scudino S, Eckert J (2014) Selective laser melting of in situ titanium–titanium boride composites: processing, microstructure and mechanical properties. Acta Mater 76:13–22.  https://doi.org/10.1016/j.actamat.2014.05.022 CrossRefGoogle Scholar
  22. 22.
    Tammas-Williams S, Zhao H, Léonard F, Derguti F, Todd I, Prangnell PB (2015) XCT analysis of the influence of melt strategies on defect population in Ti–6Al–4V components manufactured by selective electron beam melting. Mater Charact 102:47–61.  https://doi.org/10.1016/j.matchar.2015.02.008 CrossRefGoogle Scholar
  23. 23.
    Gan MX, Wong CH (2016) Practical support structures for selective laser melting. J Mater Process Tech 238:474–484.  https://doi.org/10.1016/j.jmatprotec.2016.08.006 CrossRefGoogle Scholar
  24. 24.
    Chivel Y, Smurov I (2011) Temperature monitoring and overhang layers problem. Phys Proc 12:691–696.  https://doi.org/10.1016/j.phpro.2011.03.086 CrossRefGoogle Scholar
  25. 25.
    Kasperovich G, Haubrich J, Gussone J, Requena G (2016) Correlation between porosity and processing parameters in TiAl6V4 produced by selective laser melting. Mater Des 105:160–170.  https://doi.org/10.1016/j.matdes.2016.05.070 CrossRefGoogle Scholar
  26. 26.
    Blinn B, Klein M, Gläßner C, Smaga M, Aurich J, Beck T (2018) An investigation of the microstructure and fatigue behavior of additively manufactured AISI 316L stainless steel with regard to the influence of heat treatment. Metals 8(4):220.  https://doi.org/10.3390/met8040220 CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Materials Test EngineeringTU Dortmund UniversityDortmundGermany

Personalised recommendations