Open AccessGas flow study for development of a novel shielding gas nozzle for directed energy deposition processes using computational fluid dynamic simulations
Author(s) -
Yogesh Nalam,
Tobias Hauser,
P. Breese,
Tobias Kamps,
Yves Küsters,
Rebar Hama-Saleh Abdullah,
Jöerg Volpp,
Alexander Kaplan
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1135/1/012016
Subject(s) - shielding gas , nozzle , inconel , materials science , deposition (geology) , electromagnetic shielding , flow (mathematics) , substrate (aquarium) , volume (thermodynamics) , computational fluid dynamics , mechanical engineering , alloy , chemical engineering , composite material , mechanics , thermodynamics , welding , paleontology , oceanography , physics , laser beam welding , sediment , engineering , biology , geology
Directed energy deposition (DED) enables the additive manufacturing of several materials such as molybdenum alloys that are very difficult to process by conventional methods. Some of these materials are highly reactive to gases in ambient atmosphere such as oxygen, and nitrogen. Oxidation during additive manufacturing significantly influences the mechanical properties of a part. In some cases, the shielding gas coverage of standard powder nozzles is not sufficient, and oxidation still takes place. A functional prototype of a compound multi flow path annular nozzle was developed using computational fluid dynamics simulations. Simulations were performed using multi-component miscible gas model. Prototypes were manufactured for several design iterations to test their functionality in cold flow conditions. In the end, an Inconel based prototype was built, using laser powder bed fusion. The volume of shielding gas cover over the substrate improved with the proposed design and the radial extent of 80 ppm oxygen concentration increased from 8 mm to 25 mm. Finally, Mo-Si-B alloy was deposited on a 1000 °C pre-heated substrate without significant oxidation or cracks.