Experimental characterization of Inconel 625 powder stream and single track deposited on SS400 steel by direct laser metal deposition
Year: 2026
Type: article
Abstract: Directed laser metal deposition (DLMD) offers significant potential for producing high-performance coatings and functional components, yet the effect of powder feed rate on coaxial powder stream stability and its correlation with single-track deposition quality remains insufficiently investigated. This study characterizes the Inconel 625 powder stream using light-sheet imaging and grayscale intensity analysis at feed rates of 5–30 g/min. The powder stream consistently converged at approximately 9 mm below the nozzle exit, independent of feed rate, ensuring stable alignment with the laser beam without adjusting the stand-off distance. The transverse profiles exhibited a Gaussian-like distribution. Based on these findings, single-track deposition on SS400 steel produced stable geometry, a fine cellular-to-columnar dendritic microstructure (primary dendrite arm spacing of 2.2–2.3 μm), uniform microhardness of 206.7–209.5 HV (about 25% higher than the substrate), and no porosity, lack-of-fusion, or solidification cracks. These results establish a direct link between powder stream characteristics and deposition quality, providing practical guidelines for robust DLMD processing of Inconel 625 on carbon steel substrates.
Institution: Le Quy Don Technical University
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
Funder: Le Quy Don Technical University
OpenAlex ID: W7204644664