Reduction of oxygen content in laser powder bed fusion process atmosphere – Effects on stochastic defect formation and mechanical properties
Artikel i vetenskaplig tidskrift, 2024

Stochastic defects in materials manufactured via laser powder bed fusion (LPBF) can severely compromise mechanical performance and are challenging to predict and detect, thus motivating the development of defect mitigation strategies. Particle oxidation is a factor well-known to generate defects by disturbing melt pool dynamics. If the particles are spatters, additional disturbances increase the likelihood of defect formation. In this study, restricting oxygen content in the process atmosphere to 50 ppm is investigated to minimize stochastic spatter-induced defects and improve the mechanical properties of Hastelloy X. Specimens were manufactured under this condition at two nominal layer thicknesses, analyzed for internal defects, and mechanically tested. Contrary to expectations, reducing the oxygen content did not prevent spatter-induced defect formation; rather, it could exacerbate the formation of more numerous and larger defects. Nevertheless, this tighter control of the process atmosphere led to significant microstructural refinement, which, when combined with sparse defects, resulted in improved fatigue performance. Despite the inherent ductility of Hastelloy X, the presence of abundant defects significantly larger than the microstructural characteristic size proved detrimental to fatigue performance. Notably, the occurrence of defects exhibited considerable variation across the build area, contributing to scatter in fatigue data. However, quantitative analysis of in-situ monitoring data enabled prediction of variability in defect content and mechanical performance.

Defect mitigation

Defect detection

In-situ monitoring





Claudia de Andrade Schwerz

Chalmers, Industri- och materialvetenskap, Material och tillverkning

JJ Moverare

Linköpings universitet

Alain Küng

RISE Research Institutes of Sweden

Benjamin Bircher

RISE Research Institutes of Sweden

Dmitri Riabov


Chalmers, Industri- och materialvetenskap, Material och tillverkning

Lars Nyborg

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Journal of Materials Research and Technology

22387854 (ISSN)

Vol. 30 4667-4681

Kvalitetssäkring och dynamisk respons genom on-line monitorering av additiv tillverkning

VINNOVA (2022-02549), 2022-11-08 -- 2025-11-07.

Additive Manufacturing using Metal Pilot Line (MANUELA)

Europeiska kommissionen (EU) (EC/H2020/820774), 2018-10-01 -- 2022-09-30.



Metallurgi och metalliska material



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