Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L
- Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computedRapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.…
Autor*innen: | Alexander Ulbricht |
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Koautor*innen: | Simon AltenburgORCiD, Maximilian SprengelORCiD, Konstantin Sommer, Gunther MohrORCiD, Tobias FritschORCiD, Tatiana MishurovaORCiD, Itziar Serrano MunozORCiD, Alexander Evans, Michael Hofmann, Giovanni BrunoORCiD |
Dokumenttyp: | Posterpräsentation |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2020 |
Organisationseinheit der BAM: | 8 Zerstörungsfreie Prüfung |
8 Zerstörungsfreie Prüfung / 8.0 Abteilungsleitung und andere | |
8 Zerstörungsfreie Prüfung / 8.5 Röntgenbildgebung | |
9 Komponentensicherheit | |
9 Komponentensicherheit / 9.3 Schweißtechnische Fertigungsverfahren | |
9 Komponentensicherheit / 9.4 Integrität von Schweißverbindungen | |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Freie Schlagwörter: | Additive manufacturing; Computed tomography; LPBF; Laser Powder Bed Fusion; Neutron diffraction; Residual stress; Thermography; X-ray diffraction |
Themenfelder/Aktivitätsfelder der BAM: | Material |
Material / Additive Fertigung | |
Material / Degradation von Werkstoffen | |
Veranstaltung: | MLZ User Meeting 2020 |
Veranstaltungsort: | Online meeting |
Beginndatum der Veranstaltung: | 08.12.2020 |
Enddatum der Veranstaltung: | 10.12.2020 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 10.12.2020 |
Referierte Publikation: | Nein |