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Materials Science in Additive Manufacturing AM-produced CoCrFeMnNi properties

can help to eliminate or reduce the amount of such defects • Electrochemical corrosion study revealed formation of
and therefore significantly increase impact toughness of passive film on surface of both AB samples as evident
SLM-produced CoCrFeMnNi. from anodic drift of open circuit potential test while
no such films were formed on heat-treated samples.
4. Conclusions Higher scanning speed resulted in slight decrease in
This research focuses on the effect of heat treatment corrosion resistance in the as-built materials. Heat
on microstructure and properties of SLM-produced treatment also lowered the corrosion resistance,
CoCrFeMnNi, in which the impact fracture and corrosion which is more pronounced for the materials obtained
resistance were, for the first time, studied. First, SLM at 750 mm/s.
experiments were performed with various laser scanning
speeds, and the proper ones were determined based on Acknowledgments
the evaluation on the density and porosity of obtained None.
CoCrFeMnNi. In the next step, various samples such as
Charpy impact and tensile test were prepared with the Funding
selected SLM process parameters, and heat treatment
was conducted on the obtained materials. Thereafter, None.
corrosion resistance properties, tensile properties, impact Conflict of interest
fracture, microhardness, elemental composition, and
crystallographic texture were investigated for the as-built The authors hereby declare that they have no known
and heat treated samples. The following findings can be competing financial interests or personal relationships that
summarized. could have appeared to influence the work reported in this
paper.
• Under the fixed settings of the laser power (P), hatch
spacing (H), and layer thickness (T) at 100W, 60 μm, Author contributions
and 20 μm, respectively, the laser scanning speed
between 700 and 800 mm/s was found to generate the Conceptualization: Jing Shi
highest density and lowest porosity. Data curation: Roman Savinov
• SLM-produced CoCrFeMnNi materials solidified into Formal analysis: Roman Savinov
a single-phase FCC structure. While the texture with a Investigation: Roman Savinov
strong <100> alignment was observed in the materials Methodology: Roman Savinov
obtained using 450 mm/s and 650 mm/s scanning Supervision: Jing Shi
speeds, for both before and after heat treatment, the Visualization: Roman Savinov, Jing Shi
texture of heat-treated materials was found to be Writing – original draft: Roman Savinov, Jing Shi
stronger according to the PFs. Writing – reviewing and editing: Roman Savinov, Jing Shi
• Elemental composition of obtained samples is
close to the nominal composition of equiatomic Availability of data
CoCrFeMnNi. However, small depletion of Mn was The raw/processed data required to reproduce the findings
detected especially in 450 mm/s cases, which can be can be made available on reasonable requests.
attributed to the high volatility of Mn in the SLM
process. References
• Ductility was drastically improved by the heat 1. Moghaddam AO, Shaburova NA, Samodurova MN, et al.,
treatment (increased by 59.3% and 23.2% for 2021, Additive manufacturing of high entropy alloys:
450 mm/s and 750 mm/s cases, respectively), while A practical review. J Mater Sci Technol, 77: 131–162.
the ultimate tensile strength showed only negligible
change. It could be attributed to the release of residual 2. Yeh JW, Chen SK, Lin SJ, et al., 2004, Nanostructured high‐
strain and the increase of average grain size as a result entropy alloys with multiple principal elements: novel alloy
design concepts and outcomes. Adv Eng Mater, 6: 299–303.
of heat treatment.
• Between the selected 450 mm/s and 750 mm/s 3. Eißmann N, Klöden B, Weißgärber T, et al., 2017, High-
scanning speeds, the difference in impact energy entropy alloy CoCrFeMnNi produced by powder metallurgy.
absorption was small. However, heat treatment Powder Metallurgy, 60: 184–197.
caused noticeable increase in energy absorption 4. Wang X, Guo W, Fu Y, 2021, High-entropy alloys: Emerging
(by 15.6% and 11.1% for 450 mm/s and 750 mm/s materials for advanced functional applications. J Mater
cases, respectively). Chem A, 9: 663–701.

Volume 2 Issue 1 (2023) 14 https://doi.org/10.36922/msam.42