Nitinol manufacturing and micromachining: A review of processes and their suitability in processing medical-grade nitinol

Mwangi, James Wamai; Nguyen, Linh Tuan; Bui, Viet D.; Berger, Thomas; Zeidler, Henning; Schubert, Andreas

doi:10.1016/j.jmapro.2019.01.003

Cited by 85 publications

(54 citation statements)

References 89 publications

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“…The DSC test was performed covering a temperature range between −70 °C and 100 °C, which is a region where it is safe to perform the aluminum crucible test and which coincides with the range in which phase changes are usually present in commercial alloys [3].…”

Section: Preparation For Differential Calorimetry Scanmentioning

confidence: 99%

“…Although the first shape memory alloy (SMA) has been discovered in 1932 by Arne Olander [1], the widely known nickel and titanium equiatomic alloy under the name NiTinol was discovered only in 1960 by Buheler and Wiley at the Naval Ordnance Laboratory (responsible for the suffix "nol" in the alloy name) [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…The material can change between the austenitic phase and the martensitic phase without a diffusion process, thus allowing a return to the initial geometry, even after considerable deformation, but when subjected to a certain temperature. This effect is called Shape Memory Effect [1,3,4]. While the ability to recoverable large mechanical stresses is called Superelasticity, being these two features the major differential of NiTinol from others alloys [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…This effect is called Shape Memory Effect [1,3,4]. While the ability to recoverable large mechanical stresses is called Superelasticity, being these two features the major differential of NiTinol from others alloys [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…Transformation temperatures in commercial NiTinol alloys are usually in the range of −100 °C to +100 °C, with hysteresis ranging from 30 K to 50 K, with a temperature error of ±5 °C, which corresponds to a difference of ±0.05% in alloy composition [3]. The global smart materials market moved around USD 19.6 billions in 2010, with an expected annual growth rate of 12.8% by 2016, with worldwide patents exceeding 20,000 registers [1].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Characterization Techniques of a Shape Memory Nickel Titanium Alloy

Andrade

Soares

Nobrega

et al. 2020

The 5th Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology - CIEEMAT 2019

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This paper presents a characterization processes study of metallic alloys, more specifically the shape memory alloys (SMA) composed by Nickel and Titanium (NiTinol). Two different wire suppliers were studied, starting with metallographic analysis until observe the contours of the grain wires. Differential scanning calorimetry (DSC) test was also performed to obtain phase transformation temperatures of the NiTinol alloys. Finally, after several tensile tests, some results were obtained for stresses, strains, elasticity modules and maximum rupture deformation.

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Section: Preparation For Differential Calorimetry Scanmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization Techniques of a Shape Memory Nickel Titanium Alloy

Andrade

Soares

Nobrega

et al. 2020

The 5th Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology - CIEEMAT 2019

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Shape Memory Alloys via Halide‐Activated Pack Equilibration

2022

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Shape memory alloys (SMAs), most notably those based on nearequiatomic NiTi, feature distinctive diffusionless phase transformations that give rise to useful functionalities (e.g., to generate force/motion or to store/dissipate deformation energy) that have resulted in wide-scale commercial applications across aerospace, automotive, biomedical, robotics, and other technological fields. [1] Many SMA components feature complex architectures ranging from honeycombs to cellular structures designed to lightweight system components, to match stiffness with adjoined materials, or to intensify deformation responses. [2] Unfortunately, these same phase transformations and resultant thermal-mechanical behaviors that make SMAs desirable also make their manufacture notoriously challenging. NiTi-based SMAs particularly exhibit acute sensitivity to chemistry and microstructure that can be strongly affected by thermal-mechanical histories developed during processing and service. [3] Numerous strategies have been explored to manufacture complex-shaped NiTi SMA components, including various methods for metal joining and metal additive manufacturing. [4,5] While these techniques greatly expand the catalog of accessible SMA architectures for specialized technological applications, such high-temperature processing techniques can have difficulty maintaining precise control over material chemistry. For example, selective laser melting and fusion welding techniques can cause NiTi in localized regions to greatly exceed its melting point (%1310 C), resulting in incongruent volatilization with preferential loss of nickel. The ensuing compositional shift leads to Ti-rich precipitate formation and products whose ductility and shape memory behavior may be significantly impaired. Optimization of processing parameters can reduce the magnitude of these effects, [5] but must be performed on a part-by-part basis. The development of post-processes that can precisely restore the elemental composition of heat-affected material could therefore help enable the wide application of these and other metal manufacturing techniques for NiTi-based SMAs.This work describes a method, SMAs via halide-activated pack equilibration (SHAPE), to manufacture NiTi-based SMAs with precisely controlled chemistries. The SHAPE method improves upon existing reaction-based processing routes employed to synthesize NiTi via solid-state diffusion of titanium into a target substrate. In prior work, drive-in diffusion from a gaseous phase has been accomplished by the use of titanium sponge as a vapor source in the presence of a halide transport agent [6] ; however, titanium cannot be in equilibrium with the desired product NiTi under typical process conditions (i.e., in accordance with the Ni-Ti phase diagram, [7] below 942 C titanium can only be in equilibrium with Ti 2 Ni). Consequently, target substrates in previous studies have been subject to over-titanization resulting in undesired Ti 2 Ni formation and ultimately degrading SMA performance. In the SHAPE method, targe...

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Nickel–Titanium Alloy Laser Micromachining: A Review of Nitinol Laser Processes and Optimization for High‐Speed Laser Cutting

Otto,

Vaseghi,

Davami

2024

Adv Eng Mater

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The nickel‐titanium (NiTi) alloy, “Nitinol”, has become a prominent name in the medical device industry amongst medical device manufacturers. The unique properties of the material, such as the shape memory effect and pseudoelasticity, have earned the material increasing popularity for new product innovations. Amongst the various manufacturing processes for metal alloys, laser micromachining has taken the lead for processing Nitinol‐based products. This literature review provides an analysis of the history and applications of Nitinol, an overview of the microstructure of the material, and a review of the current manufacturing methods for laser cutting medical‐grade Nitinol. A more in‐depth focus is placed on the realm of laser processing and the challenges associated with the manufacturing process. Ultrafast femtosecond pulse processing delivers promising results and quality for manufacturing Nitinol medical devices. However, there exists a need to investigate potential approaches to increase the cutting speed of the process to enhance throughput and stay competitive in a growing market due to the cutting speed being over 4‐times slower than long pulse cutting. Many tactics to address the problem are discussed, ranging from laser selection, processing parameters, and non‐traditional laser processing approaches.This article is protected by copyright. All rights reserved.

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Nitinol manufacturing and micromachining: A review of processes and their suitability in processing medical-grade nitinol

Cited by 85 publications

References 89 publications

Characterization Techniques of a Shape Memory Nickel Titanium Alloy

Characterization Techniques of a Shape Memory Nickel Titanium Alloy

Shape Memory Alloys via Halide‐Activated Pack Equilibration

Nickel–Titanium Alloy Laser Micromachining: A Review of Nitinol Laser Processes and Optimization for High‐Speed Laser Cutting

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