Page 448 - IJB-10-4

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

Figure 12. Mechanical properties of the laser powder bed fusion (LPBF)-fabricated Zn–Mg alloy after annealing at different parameters: (a) stress–strain
responses; (b) tensile strength and elongation; and (c) a comparison of tensile properties of Zn–Mg alloys. 14,26,27,46–48

the cleavage planes (~5 μm) compared to those observed during tensile deformation and resulting in higher tensile
in the Zn–Mg alloy annealed at 250℃. In Figure 13c, the strength of the as-built alloy. However, after annealing,
cleavage plane dimensions of the Zn–Mg alloy annealed the average grain size of Zn–1Mg alloy increased from
at 365℃ (~10 μm) fell between those observed in the Zn– 0.74 to 1.06 μm, leading to predominantly equiaxed
Mg alloys annealed at both 250 and 300℃. As observed grains in the annealed Zn–Mg alloy. The increase in
in Figure 13, annealing of the Zn–1Mg alloy exhibited grain size resulted in a decrease in grain boundaries
no evident signs of plastic deformation but displayed within the annealed Zn–Mg alloy and subsequently
cleavage fracture characteristics, such as river patterns, on reduced dislocation movements generated during tensile
its morphology. deformation, ultimately decreasing the tensile strength
but increasing the plasticity of the Zn–Mg alloy. From the
After annealing at 300°C for 0.5 h, the ultimate tensile EBSD characterization (Figure 11a and d), fewer low-angle
strength of the Zn–1Mg alloy decreased by 32.9%, while grain boundaries were observed within the annealed alloy
the elongation increased by a factor of 14.3. It could also compared to those found within the as-built alloy, further
be observed from Figure 11b and e that the as-built alloy validating that annealing effectively reduced dislocation
exhibited bimodal grains with numerous dislocations density in the Zn–Mg alloy. The reduction in dislocations
between grains of different sizes, thereby enabling leads to a decrease in slip systems available for deformation
mechanical reinforcement mechanisms, such as grain during the tensile process, decreasing the tensile strength
boundary reinforcement and dislocation reinforcement, but increasing the plasticity of the annealed Zn–Mg alloy.

Volume 10 Issue 4 (2024) 440 doi: 10.36922/ijb.3034