Page 106 - MSAM-4-3

Materials Science in Additive Manufacturing Heterostructures of A131 steel by DED

(i) The AB A131 steel exhibited a high σ of 929.5 MPa Author contributions
YS
and σ UTS of 970.4 MPa, approximately 168% and
78% enhancement compared to those of commercial Conceptualization: Yuchao Bai
A131 steel (σ : 346.5 MPa; σ UTS : 545.0 MPa), with an Formal analysis: Jiaming Zhan, Silu Zhang
YS
elongation of 24.5%. After HT, the strength of A131 Investigation: Yuchao Bai, Qi Yan
steel was significantly reduced compared to that Methodology: Yuchao Bai, Silu Zhang
before tempering, when retaining 70% enhancement Data Curation and Visualization: Qi Yan, Cuiling Zhao
in σ compared to commercial A131 steel. Writing – original draft: Yuchao Bai
YS
(ii) The A131 steel fabricated by DED methods possesses Writing – review & editing: Qi Yan, Cuiling Zhao
a significant heterostructure comprising alternating Funding acquisition: Yuchao Bai
layers of coarse- and fine-grain sections (~300 µm Ethics approval and consent to participate
thick), formed due to dendritic growth and thermal
cycling. The coarse-grain region mainly consisted of Not applicable.
fine columnar grains and acicular martensite, while
the fine-grain region featured small equiaxed crystals Consent for publication
and fine martensite. Not applicable.
(iii) Tempering treatment of AB A131 steel induced
martensite-to-ferrite phase transformation and grain Availability of data
growth into equiaxed structures, reducing crystal Data is available from the corresponding author upon
misorientation and anisotropy in the microstructure reasonable request.
but significantly decreasing mechanical strength.
(iv) The heterostructure induced notable anisotropy in References
tensile performance, where the tensile properties and
hardness of the A131 steel along ND significantly 1. Kuntanapreeda S, Hess D. Opening access to space by
exceeded those in TD. HD had limited impact on maximizing utilization of 3D printing in launch vehicle design
and production. Appl Sci Eng Prog. 2021;14(2):143-145.
reducing anisotropy, even resulting in a 4.6% decrease
in σ UTS along TD compared to commercial A131 steel. doi: 10.13316/j.asep/2020/12.002
(v) MD simulations demonstrated that uniaxial load 2. Liu S, Shin YC. Additive manufacturing of Ti6Al4V alloy:
at ND promoted uniform deformation, enhancing A review. Mater Des. 2019;164:107552.
strength and elongation. In contrast, applied load doi: 10.1016/j.matdes.2018.107552
along TD could induce partial stress concentration
and necking, reducing both tensile strength and 3. Liu TS, Chen P, Qiu F, et al. Review on laser directed
plasticity. energy deposited aluminum alloys. Int J Extreme Manuf.
2024;6(2):022004.
Acknowledgments doi: 10.1088/2631-7990/ad16bb
None. 4. Zhang B, Gao Z, Xiao H, Yang X, Li Y, Zhu H. Size effects
and optimization during laser directed energy deposition
Funding on high thermal conductivity copper alloys. J Mater Res
This study was funded by the Guangdong Basic and Technol. 2024;33:4389-4399.
Applied Basic Research Foundation (2023A1515110594; doi: 10.1016/j.jmrt.2024.10.104
2024A1515012049), Shenzhen Science and 5. Bai Y, Chaudhari A, Wang H. Investigation on the
Technology Program (JCYJ20241202123701003; microstructure and machinability of ASTM A131 steel
QTD20210811090146075), and Shenzhen Natural manufactured by directed energy deposition. J Mater Process
Science Fund (Stable Support Plan Program; Technol. 2020;276:116410.
GXWD20231129161359002).
doi: 10.1016/j.jmatprotec.2019.116410
Conflict of interest 6. Gu D, Shi X, Poprawe R, Bourell DL, Setchi R, Zhu J.
Material-structure-performance integrated laser-metal
Yuchao Bai serves as the Guest Editor of the Special Issue, additive manufacturing. Science. 2021;372(6545):eabg1487.
but was not in any way involved in the editorial and
peer-review process conducted for this paper, directly or doi: 10.1126/science.abg1487
indirectly. Other authors declare they have no competing 7. Seedhouse E, editor. Falcon 9 and falcon heavy. In: SpaceX:
interests. Starship to Mars The First 20 Years. New York: Springer

Volume 4 Issue 3 (2025) 13 doi: 10.36922/MSAM025220038