Author Identifier (ORCID)

J. C. Wang: https://orcid.org/0000-0003-2476-928X

L. C. Zhang: https://orcid.org/0000-0003-0661-2051

Abstract

Compared to other loading conditions, studies on deformation mechanisms of additive manufacturing (AM)-produced β-type Ti alloys under bending remain limited. This study investigates a metastable β-type Ti–25Nb–3Zr–3Mo–2Sn (TLM, wt.%) alloy fabricated via laser powder bed fusion (L-PBF) during in-situ three-point bending. In-situ observations using scanning electron microscopy (SEM) combined with electron backscatter diffraction (EBSD) and ex-situ transmission electron microscopy (TEM) imaging during bending provided evaluation of microstructural changes and deformation mechanisms. These mechanisms are characterized by dislocation slip, {332}<113>β deformation twin, α" phase, and ω phase formation during plastic bending stage. The {112}<111> slip system dominates in the compression zone, while the {123}<111> slip system governs in the tension zone during bending. The synergistic effect of twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) significantly enhances the ductility of L-PBF-produced TLM alloy. The deformation involves stress-induced α" and ω phases, with the latter can form within grains/twinning band and at twinning boundaries. Importantly, the presence of the interfacial twin boundary (ITB)-ω thin layers at twinning band boundaries exerts a pinning effect, restraining the outward extension of stress-induced α" phase. This mechanism suggests optimized utilization of space within twinning bands, facilitating α" nucleation and uniform growth, thereby providing insights into further enhancing ductility.

Document Type

Journal Article

Date of Publication

3-1-2025

Volume

925

Publication Title

Materials Science and Engineering: A

Publisher

Elsevier

School

Centre for Advanced Materials and Manufacturing / School of Engineering

Funders

Edith Cowan University (23965) / National Natural Science Foundation of China (52404382) / Australian Government Research Training Program Scholarship / Forrest Research Foundation / TechWorks FutrueLab at The University of Western Australia / Woodside Energy Group Ltd

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Comments

Ma, H. Y., Wang, J. C., Liu, Y. J., Li, Y. H., Zhang, Y. S., Liu, X. C., & Zhang, L. C. (2025). In-situ microstructural evolution and deformation mechanisms of metastable beta titanium fabricated by laser powder bed fusion under flexural stress. Materials Science and Engineering: A, 925, 147873. https://doi.org/10.1016/j.msea.2025.147873

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Link to publisher version (DOI)

10.1016/j.msea.2025.147873