Effects of Heat Treatment on Ti–ni–cu/tini Shape Memory Bimetal Fabricated by Directed Energy Deposition

Abstract

A Ti–Ni–Cu/TiNi bi-metallic shape memory alloy structure was fabricated via laser directed energy deposition with powder blend of Ti, Ni, and Cu elemental powders. Subsequently, part of the as-deposited bi-metallic shape memory alloy underwent heat treatment at 400 °C and 600 °C. Microstructural, mechanical, and functional properties of the bi-metallic structure in its as-deposited state and after both heat treatment states were characterized across various locations to investigate variations in multifunctional features and shape memory behaviors. Microstructural analysis revealed that the Ti-rich Ti–Ni–Cu ternary alloy section exhibited no obvious change among different heat treatment conditions. On the contrary, within the TiNi substrate, the laser-induced heat during the deposition process created location-dependent microstructural features and properties, and subsequent heat treatments further diversified the mechanical and thermal behaviors and yielded a broader range of behavior combinations. This work demonstrates the potential of combining directed energy deposition with heat treatment to develop multi-sectional shape memory alloys with greater flexibility, lower cost, and a wider range of memory effect combinations.

Department(s)

Mechanical and Aerospace Engineering

Comments

Intelligent Systems Center, Grant CMMI 1625736

Keywords and Phrases

Additive manufacturing; Bi-metallic structure; Directed energy deposition; Multifunctional materials; Shape memory alloy

International Standard Serial Number (ISSN)

1044-5803

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

01 Dec 2025

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