In this paper, a TiNiCu shape memory alloy single-wall structure was fabricated by the directed energy deposition technique with a mixture of elemental Ti, Ni, and Cu powders following the atomic percentage of Ti50Ni45Cu5 to fully utilize the material flexibility of the additive manufacturing process to develop ternary shape memory alloys. The chemical composition, phase, and material properties at multiple locations along the build direction were studied, using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Vickers hardness test-ing, tensile testing, and differential scanning calorimetry. The location-dependent compositions of martensitic TiNi and austenitic TiNi phases, mechanical properties, and functional properties were investigated in detail. Variations were found in atomic compositions of Ti, Ni, and Cu elements along the build direction due to the complex interaction between elemental powders and laser pro-cessing. Good correlations were present among the chemical composition, phase constituent, hard-ness, and feature of phase transformation temperatures at various locations. The ultimate tensile strength of the as-deposited TiNiCu alloy is comparable with the previously reported additively manufactured TiNi binary alloys. By adding Cu, a much lower thermal hysteresis was achieved, which shows good feasibility of fabricating ternary TiNiCu shape memory alloys, using elemental powders in the directed energy deposition to adjust the thermal hysteresis.


Materials Science and Engineering

Second Department

Mechanical and Aerospace Engineering

Research Center/Lab(s)

Intelligent Systems Center


This research was funded by NSF, grant number CMMI 1625736.

Keywords and Phrases

Additive Manufacturing; Directed Energy Deposition; Elemental Powder Blends; Material Characterization; Shape Memory Alloys; Ternary TiNi Alloys

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

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

Publication Date

01 Jun 2021