Journal Article

Enhancing Shape Memory Response of Additively Manufactured Niti Shape Memory Alloys by Texturing and Post-Processing Heat Treatment

Toker, Guher Pelin, Saghaian, Sayed M., Anderoglu, Osman, Elahinia, Mohammad, Moghaddam, Narges Shayesteh, Karaca, Haluk, Radhakrishnan, Madhavan, Saghaian, Sayed E., Nematollahi, Mohammadreza

2023

Overview

This study presents the shape memory behavior of Ni-rich NiTi shape memory alloy fabricated by Laser Powder Bed Fusion Additive Manufacturing (L-PBF-AM) before and after post-processing heat treatment. The microstructural features and thermo-mechanical responses were systematically investigated to understand the effects of processing on the behavior of the specimens. It was shown that the L-PBF-AM process improves the functionality of NiTi components by illustrating perfect superelastic behavior at higher-temperature windows compared to the casted ingot. In addition, it was revealed that shape memory responses were tailored by altering hatch distance, which significantly controls the texture formation along the building direction. After post-processing treatments, transformation temperatures were increased, hysteresis was decreased, and the strength of the samples was significantly improved. The aged L-PBF-AM sample with a smaller hatch distance (80 µm) and intense [001] texture illustrated perfect superelastic behavior with a recoverable strain of 7% and a superelastic temperature span of about 100 °C.

• Publisher: Springer US,Springer Nature B.V
• Subject: Additive manufacturing / Aging / Characterization and Evaluation of Materials / Chemistry and Materials Science / Cooling / Heat treating / Heat treatment / Ingot casting / Intermetallic compounds / Lasers / Martensitic transformations / Materials Science / Microstructure / Morphology / Nickel base alloys / Nickel compounds / Nickel titanides / Powder beds / Recoverable strain / Shape memory alloys / Superelasticity / Technical Article / Temperature / Texture / Texturing / Transformation temperature