Impact of processing gas composition on process stability and properties of PBF-LB/M processed alloy 718
Artikel i vetenskaplig tidskrift, 2024

The almost unlimited design freedom of the laser-based powder bed fusion of metals (PBF-LB/M) makes this technology very attractive for industry. However, as a developing technology, it still faces some challenges when it comes to productivity and robustness, to name some. Whereas numerous studies covered the impact of laser-based parameters on material properties and robustness, the effect of the processing gas received limited attention. The objective of this study was to evaluate the effect of processing gas composition, containing helium (He) and hydrogen (H2), compared to conventionally used argon (Ar), during PBF-LB/M processing of virgin alloy 718 powder, on printing behavior and part properties. The four gases studied were Ar, Ar +30%He, Ar +30%He +2%H2, and Ar +70%He. Optical Tomography (OT) was used to monitor process stability, which unveiled a significant decrease in process-by products (spatters) between 51 % and 89 % using He and H2-containing gases. It was also found that the process gas decreased the bulk porosity from an average value of 0.08 % when processed with Ar to 0.04 % when using Ar + 70%He. The oxygen pickup by the spatter particles was reduced from 630 ppm (Ar) to 331 ppm (Ar +70%He). EBSD analysis revealed that there were no evident changes in microstructure with the processing gas. The samples processed also had similar tensile properties with yield and ultimate tensile strength of 1180 MPa and 1395 MPa, respectively. However, there was a slight increase in ductility from 16.5 % to 17.2 %, when processed with pure Ar and Ar + 70%He, respectively. This study shows that utilizing standard Ar processing atmosphere with He addition leads to a more stable process with reduced spatter, porosity and a marginal increase in ductility for Alloy 718.

Optical tomography

EBSD

PBF-LB/M

Alloy 718

Process gas

Hydrogen

Helium

Författare

Tobias Deckers

Universität Duisburg-Essen

Linde GmbH

Ahmed Fardan Jabir Hussain

Chalmers, Industri- och materialvetenskap, Material och tillverkning

L. Kersting

Siemens

A. Kreutzer

Siemens

Pierre Forêt

Linde GmbH

S. Dubiez-Le Goff

Linde GmbH

G. Witt

Universität Duisburg-Essen

S. Kleszczynski

Universität Duisburg-Essen

Uta Klement

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Eduard Hryha

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Journal of Manufacturing Processes

1526-6125 (ISSN)

Vol. 120 712-718

Ämneskategorier

Bearbetnings-, yt- och fogningsteknik

Kemiska processer

Metallurgi och metalliska material

Styrkeområden

Materialvetenskap

DOI

10.1016/j.jmapro.2024.04.061

Mer information

Senast uppdaterat

2024-05-21