Authors:

HyunJoong Kim (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)
Sung-Jae Jo (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)
Jongun Moon (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)
Jiwoon Lee (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)
Gian Song (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)
Soon-Jik Hong (Division of Advanced Materials Engineering, and Center for Advanced Materials and Parts of Powders (CAMP2), Kongju National University, Korea, Republic of)

Abstract:

Powder characteristics in Directed Energy Deposition (DED) processes significantly impact the final product quality, yet the role of moisture content remains underexplored. This study evaluates the impact of varying powder humidity levels on flowability, microstructure, and mechanical properties during the DED process. Powder with different moisture levels were analyzed for particle size distribution, moisture content, and oxide layer thickness. Results from Hall Flowmeter and Dynamic Avalanche testing revealed that higher moisture content reduced flowability. When applied to the DED process, reduced flowability affected the dimensional accuracy and surface roughness of the resulting alloys. Microstructural analysis showed that elevated moisture levels promoted coarse oxide formation, identified as MnSiO3 and Cr2O3 through EBSD analysis. Tensile tests revealed that the oxides decreased tensile strength and elongation. These findings highlight the necessity of maintaining low humidity storage conditions or pre-drying powders to ensure high-quality, defect-free components in AM processes.

DOI:

https://doi.org/10.59499/EP256779291