PSI - Issue 69

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ScienceDirect

Procedia Structural Integrity 69 (2025) 121–126

13th European Symposium on Martensitic Transformation 2024 (ESOMAT 2024) Laser shape setting feasibility for promoting shape memory effect in thin Ti rich-NiTi wires Carlo Alberto Biffi a, *, Gloria Ischia b , Stefano Gialanella b , Ausonio Tuissi a

a CNR-ICMATE, National Research Council of Italy – Institute of Condensed Matter Chemistry and Technologies for Energy, Via Previati 1E, Lecco, 23900, Italy. b Università degli Studi di Trento, Industrial Engineering Department, Via Sommarive 9, 38123 Povo, Italy.

Abstract Shape setting is a crucial step in the production route for NiTi Shape Memory Alloys (SMAs) for tuning the final functional performances. A laser beam can be effectively used as an alternative method for a fast shape setting of NiTi wires, with the goal of inducing martensitic transformation and the corresponding thermo-mechanical response. In this work, Ti rich NiTi wires were subjected to laser scanning for inducing Shape Memory Effect. The feasibility of the laser heat treatment was studied by exploring the effect of the principal laser parameters, such as laser power and scanning speed, on the promotion of the martensitic transformation. It was demonstrated that laser shape setting can be successfully carried out on thin Ti rich NiTi wires for promoting the martensitic transformation in a temperature range of interest for promising SME performance. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Guest Editors

Keywords: Niti SMA, thin NiTi wires, shape setting, laser annealing, microstructure, functional properties.

1. Introduction Shape Memory Alloys (SMAs) require dedicated final heat treatments or thermo-mechanical processes to achieve optimal functional performance. Eventually, the high-temperature shape to be recovered by Shape Memory Effect

* Corresponding author. Tel.: +39-0341-2350111. E-mail address: carloalberto.biffi@cnr.it

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Guest Editors 10.1016/j.prostr.2025.07.017