Origin of premature fracture and enhancement of superelasticity in laser additively manufactured Ni-rich NiTi metamaterials

Journal article (2025)

Authors

Z. Yan Team Vera Popovich - Mechanical, Maritime and Materials Engineering
Jia-Ning Zhu Team Vera Popovich - Mechanical, Maritime and Materials Engineering
Yi Chieh Yang Technical University of Denmark (DTU)
J.C. Brouwer Team Marcel Hermans - Mechanical, Maritime and Materials Engineering
A.C. Riemslag Team Vera Popovich - Mechanical, Maritime and Materials Engineering
Joerg R. Jinschek Technical University of Denmark (DTU)
M. J.M. Hermans Team Marcel Hermans - Mechanical, Maritime and Materials Engineering
J. Jovanova Transport Engineering and Logistics - Mechanical, Maritime and Materials Engineering
Vera A. Popovich Team Vera Popovich - Mechanical, Maritime and Materials Engineering
Research Group
Team Vera Popovich (Mechanical, Maritime and Materials Engineering) (TU Delft)
More Info
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Published Date

2025

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Materials Science and Engineering

Research Group

Team Vera Popovich

Abstract

Superelastic metamaterials have attracted significant attention recently, but achieving such functionality remains challenging due to partial superelasticity and premature fracture in additively manufactured components. To address these issues, this study investigates the premature fracture in Ni-rich NiTi metamaterials fabricated by laser powder bed fusion. A comparative analysis of two structures (Gyroid network and Diamond shell) reveals that the structural stability of bending- and stretching-dominated structures is reversed compared to typical elastic-plastic response, due to the tension-compression asymmetry of base NiTi. The premature fracture and partial superelasticity of these as-fabricated samples are attributed to low deformation ability for accommodating tensile stress. Based on these findings, a heat treatment introducing Ni4Ti3 precipitates was employed, successfully achieving macroscopic superelasticity in the NiTi metamaterials, with consistency between model prediction and experiments.