Page 20 - MSAM-1-4

Materials Science in Additive Manufacturing Y O influence in heat-treated LPBF IN718 composite
2 3

A B

Figure 15. Schematics showing the difference in the distribution of Nb in the microstructures between samples 1275A-0 (A) and 1275A-Y (B).

4. Conclusions (NTU). The authors would like to thank Mr. Min Hao Goh
for his assistance with the SEM-EDX analysis and Dr. Li
The influence of Y O addition on the microstructures of Tao for his assistance with the heat treatment.
2
3
heat-treatedLPBFIN718 samples is investigated, and the
results are as follows. Funding
(i) Y O nanoparticles have a high tendency to combine The financial support from the A*STAR Structural and
2
3
with carbonitride precipitates to form complex Metal Alloys Program (SMAP): Work Package II with
precipitates. These complex precipitates separate into project No. A18B1b0061 is acknowledged.
individual Y O and TiN nanoparticles after heat
3
2
treatment. At the same time, Y-Ti-O precipitates Conflict of interest
form during the heat treatment due to the release of The authors declare that they have no known competing
supersaturated Y in the matrix.
(ii) Grain refinement is observed in the Y O -reinforced financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
2
3
composite after heat treatment due to the high number
of nano-sized precipitates acting as nucleation centers Author contributions
for the recrystallization of grains and suppressing
grain growth as a result of the Zener pinning effect. Conceptualization: Duy Nghia Luu and Wei Zhou
(iii) Thinner segregated regions are observed at the grain Formal analysis: Duy Nghia Luu
boundaries of the heat-treated Y O -reinforced Investigation: Duy Nghia Luu
2
3
composite. This leads to a more homogeneous Methodology: Duy Nghia Luu
distribution of Nb in the microstructures and results Project administration: Wei Zhou and Sharon Mui Ling Nai
in a smaller difference in the γ′ and γ′′ precipitates Resources: Wei Zhou and Sharon Mui Ling Nai
distribution between the regions near and far from the Supervision: Wei Zhou and Sharon Mui Ling Nai
grain boundaries. Validation: Wei Zhou and Sharon Mui Ling Nai
(iv) The value added of the reinforcement particles Visualization: Duy Nghia Luu
in strengthening IN718 is only realized after heat Writing – original draft: Duy Nghia Luu
treatment. The higher strengths of the composites Writing – review and editing: Wei Zhou and Sharon Mui
are the result of the increased Orowan strengthening Ling Nai
from a significantly higher number of nano-sized References
precipitates, the grain boundary strengthening effect,
and the γ′ and γ′′ precipitates being distributed more 1. Ibrahim IA, Mohamed FA, Lavernia EJ, 1991, Particulate
homogeneously. reinforced metal matrix composites-a review. J Mater Sci,
26: 1137–1156.
Acknowledgments https://doi.org/10.1007/BF00544448

The work is supported by the A*STAR Graduate Academy 2. Gu DD, Meiners W, Wissenbach K, et al., 2012, Laser
(A*GA) and by the Nanyang Technological University additive manufacturing of metallic components: Materials,

Volume 1 Issue 4 (2022) 14 https://doi.org/10.18063/msam.v1i4.25