Origami-Inspired Shape Memory Folding Microactuator

Seigner, Lena; Безсмертна, О. В.; Fähler, S.; Tshikwand, Georgino Kaleng; Wendler, Frank; Kohl, Manfred

doi:10.3390/iecat2020-08480

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…[3] Last but not least, our approach is feasible for micromachining of self-folding origami, which utilizes NiTi as bending actuators and switchable Heusler alloys as fixtures. [46] These examples illustrate that monolithic micromachining of partly freestanding devices is possible, without the need of manually transferring epitaxial grown films and patterns to another substrate. [6,42,47] Thus, our approach allows for batch fabrication, which is decisive for both, further miniaturization and future mass production.…”

Section: Resultsmentioning

confidence: 99%

Integration of Multifunctional Epitaxial (Magnetic) Shape Memory Films in Silicon Microtechnology

Fink,

Kar,

Lünser

et al. 2023

Adv Funct Materials

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Magnetic shape memory alloys exhibit various multifunctional properties, which range from high stroke actuation and magnetocaloric refrigeration to thermomagnetic energy harvesting. Most of these applications benefit from miniaturization and a single crystalline state. Epitaxial film growth is so far only possible on some oxidic substrates, but they are expensive and incompatible with standard microsystem technologies. Here, epitaxial growth of Ni–Mn–based Heusler alloys with single crystal‐like properties on silicon substrates is demonstrated by using a SrTiO3 buffer. It is shown that this allows using standard microfabrication technologies to prepare partly freestanding patterns. This approach is versatile, as its applicability for the NiTi shape memory alloy is demonstrated and spintronic and thermoelectric Heusler alloys are discussed. This paves the way for integrating additional multifunctional effects into state‐of‐the‐art microelectronic and micromechanical technology, which is based on silicon.

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Section: Resultsmentioning

confidence: 99%

Integration of Multifunctional Epitaxial (Magnetic) Shape Memory Films in Silicon Microtechnology

Fink,

Kar,

Lünser

et al. 2023

Adv Funct Materials

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show abstract

“…Due to its low modulus of elasticity and its functional properties, the biomedical sector is one of the most important areas for NiTi applications, e.g., stents or implants [4]. In addition, the material has a high potential in terms of new sustainable technologies, e.g., heating and cooling using the elastocaloric effect [5], newly designed actuators [6] or heat engines without the usage of fossil fuels [7]. The combination of NiTi and additive manufacturing (AM), especially powder bed fusion (PBF), has gained significant interest over the last years [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Conventional processes such as casting can have a higher probability of impurity pick-up compared to electron beam powder bed fusion (PBF-EB), which operates under high vacuum [8]. Extensive post-processing [13] can be avoided due to nearnet-shape production, and the high freedom of design enables the development of new applications [5,6]. Furthermore, PBF-EB enables a high powder bed temperature of more than 800 °C, which suppresses cracking and residual stresses, making it possible to produce crack-sensitive materials such as NiTi [9,12,14] or other crack-sensitive materials with even the possibility to tailor the microstructure by controlling the thermal conditions [15,16].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Superelastic and Shape Memory Effect of Nitinol Manufactured by Electron Beam Powder Bed Fusion

Fink,

Wahlmann,

K鰎ner

2024

Advanced Materials &Amp; Sustainable Manufacturing

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This study explores the impact of energy input and build orientation on the anisotropic mechanical and functional properties of Ti-rich Nitinol (NiTi) produced via electron beam powder bed fusion (PBF-EB), integrated with layerwise in-situ monitoring of the melted surface via backscatter electron detection (ELO). NiTi, a binary alloy of nickel and titanium, exhibits shape memory and superelasticity, making it widely used in biomedical applications and sustainable technologies. PBF-EB, particularly with ELO, is highlighted for its advantages in producing crack-free NiTi with tailored microstructures. The investigation reveals that energy input significantly influences microstructure phases, with higher energy promoting increased evaporation of Ni and enhancing Ti-rich Ti2Ni precipitates, allowing for tailored material properties. Build orientation also proves crucial, impacting mechanical responses and functional properties. The 0° orientation yields the hardest mechanical response with the highest ultimate tensile strength (UTS) and the highest strain recovery ratio while the 45° orientation shows improved ductility but lower UTS. The influencing factors towards the formation of the anisotropic material properties are explained and the potential of tailoring the NiTi properties for specific applications by controlling energy input and build orientation in the PBF-EB process are underlined. These insights offer valuable criteria for designing innovative NiTi parts.

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Functional properties and shape memory effect of Nitinol manufactured via electron beam powder bed fusion

Fink

Körner

2023

Materialia

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Origami-Inspired Shape Memory Folding Microactuator

Cited by 4 publications

References 10 publications

Integration of Multifunctional Epitaxial (Magnetic) Shape Memory Films in Silicon Microtechnology

Integration of Multifunctional Epitaxial (Magnetic) Shape Memory Films in Silicon Microtechnology

Anisotropic Superelastic and Shape Memory Effect of Nitinol Manufactured by Electron Beam Powder Bed Fusion

Functional properties and shape memory effect of Nitinol manufactured via electron beam powder bed fusion

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