Page 440 - IJB-10-4

International Journal of Bioprinting Improving ductility of 3D-printed Zn–Mg

Figure 4. Printability of laser powder bed fusion (LPBF)-fabricated Zn–Mg alloy with 3 wt% Mg: (a) width of single tracks, (b) optical microscopy image
of single tracks, (c) relative density variation, and (d) optimized process parameter window. Abbreviation: Ev, volume energy density.

the LPBF-fabricated Zn–Mg alloy exhibited the highest indicative of ZnO were observed, signifying the absence
relative density at 98.62%. All the fabricated Zn–Mg alloys of oxidation in the vacuum environment during the LPBF
achieved optimal densification at the laser power of 80 W process. From the phase diagram for Zn–Mg alloys, the
and scanning speed at 600–800 mm/s. precipitation of Mg Zn and MgZn phases occurred at
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approximately 364°C.
3.2. Microstructure of fabricated Zn–Mg alloys
The XRD results of the LPBF-fabricated Zn–Mg alloys The morphology and corresponding element
with different Mg concentrations are depicted in Figure distributions of LPBF-fabricated Zn–Mg alloys are
5. Initially, the diffraction peaks that corresponded to the presented in Figure 6. In Figure 6a, d, and g, the grain
hexagonal close-packed crystal structure of α-Zn were size of Zn–Mg alloys decreased with increasing Mg
observed in the fabricated Zn–Mg alloys at all compositions. concentration. The grain sizes were approximately 1–2,
Subsequently, no distinct diffraction peaks of Mg Zn 0.5–1, and 0.5 μm for Zn–1Mg, Zn–3Mg, and Zn–5Mg,
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were obtained in the Zn–1Mg alloy with a predominant respectively. The addition of Mg primarily contributed to
α-Zn phase due to its lower Mg concentration. In contrast, grain refinement in Zn–1Mg, while eutectic structures
both Mg Zn and MgZn phases were identified in became more pronounced in Zn–3Mg (indicated by dark
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the Zn–3Mg and Zn–5Mg alloys, and their intensities regions). Additionally, irregular polyhedral second-phase
increased significantly with increasing Mg concentration. structures were significantly present in Zn–5Mg. Elemental
Notably, higher intensity peaks of Mg Zn and MgZn composition analysis using EDS illustrated the presence of
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were achieved in the Zn–5Mg alloy. Additionally, no peaks α-Zn matrix and a second phase in LPBF-fabricated Zn–
Volume 10 Issue 4 (2024) 432 doi: 10.36922/ijb.3034