Mitigating oxygen pick-up during laser powder bed fusion of Ti-6Al-4V by limiting heat accumulation
Journal article, 2021

The dissolution of oxygen in Ti-6Al-4V during laser powder bed fusion (L-PBF) is a limitation for the final ductility of the produced components and a challenge for the end-users. In the present work, the effect of the residual oxygen in the process atmosphere of a laboratory scale L-PBF machine, as well as the role of heat accumulation, are studied. It was shown that oxygen content in the as-built Ti-6Al-4V is determined by the size of the scanned area and build time. The heat accumulation aspect was investigated by adjusting the inter-layer time (ILT), by increasing the recoating time or the number of produced parts. The results showed that oxygen pick-up could be limited by reducing residual oxygen level in the atmosphere or heat accumulation. A 400 ppm O2 reduction measured at the top of a 70 mm column was achieved by increasing the ILT manually by 4.5s, and a 1200 ppm O2 reduction by increasing the scanned area by 7 times. By doing so, the hardness at full height was reduced by approximately 30 HV10. It is shown that design features characterised by high aspect ratio can absorb significant amount of oxygen resulting in increased brittleness.

Metals and alloys

3D printing

process atmosphere

laser powder bed fusion

Ti-6Al-4V

Laser processing

Author

Camille Nicole Géraldine Pauzon

Chalmers, Industrial and Materials Science, Materials and manufacture

Kai Dietrich

University of Duisburg-Essen

Pierre Forêt

Linde GmbH

Eduard Hryha

Chalmers, Industrial and Materials Science, Materials and manufacture

Gerd Witt

University of Duisburg-Essen

Materials Letters

0167-577X (ISSN)

Vol. 288 129365

Subject Categories

Materials Engineering

DOI

10.1016/j.matlet.2021.129365

More information

Latest update

2/25/2021