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Materials Science in Additive Manufacturing Additive manufacturing of 316L-Cu alloys

A

B

C

Figure 1. Microstructure of 316L and Cu-alloyed compositions. (A) 316L control composition displayed a mix of cellular and columnar structures visible
in high magnification (B and C) SS-3Cu and SS-5Cu showed microstructures similar to those of the control composition (left column is ×200, right column
is ×1000)

the height of the samples, suggesting a consistent hardness growth (Figure 5C1-3). Quantification of visible CFU
distribution along the build direction. is summarized in Figure 5D, while the normalized
bacterial viability is presented in Figure 5E. On SS-3Cu
3.3. In vitro S. aureus bacterial study surfaces, S. aureus colonization decreased from 30% at
Cu is known for its antibacterial properties and was 24 h to 25% at 48 h and 18% at 72 h. This corresponds
expected to reduce bacterial surface colonization when to a 5% reduction between 24 h and 48 h and a 7%
incorporated into 316L. 7,10 Gram-positive S. aureus reduction between 48 h and 72 h. SS-5Cu surfaces
was tested on the metal surfaces at 24, 48, and 72 h, displayed superior antibacterial performance, with
simulating the time points immediately following remaining CFU values of 19% at 24 h, 14% at 48 h,
a surgical procedure. As shown in Figure 5A1-3, and 12% at 72 h, reflecting 5% and 2% reductions
the 316L control surfaces were heavily colonized by between respective time points. The antibacterial
S. aureus. In contrast, Cu addition reduced bacterial efficacy followed a logarithmic trend, with the most
colonization on the treated surfaces. The SS-3Cu significant reduction occurring within the first 24 h.
samples demonstrated lower CFU counts at all-time While the rate of antibacterial performance slowed at
points (Figure 5B1-3), while the SS-5Cu samples later time points, incremental improvements in efficacy
exhibited even more significant reductions in bacterial were observed. Notably, the inset image in Figure 5C1

Volume 4 Issue 1 (2025) 5 doi: 10.36922/msam.7357