Investigation into the Hybrid Production of a Superelastic Shape Memory Alloy with Additively Manufactured Structures for Medical Implants

The demographic change in and the higher incidence of degenerative bone disease have resulted in an increase in the number of patients with osteoporotic bone tissue causing. amongst other issues, implant loosening. Revision surgery to treat and correct the loosenings should be avoided, because of the additional patient stress and high treatment costs. Shape memory alloys (SMA) can help to increase the anchorage stability of implants due to their superelastic behavior. The present study investigates the potential of hybridizing NiTi SMA sheets with additively manufactured Ti6Al4V anchoring structures using laser powder bed fusion (LPBF) technology to functionalize a pedicle screw. Different scanning strategies are evaluated, aiming for minimized warpage of the NiTi SMA sheet. For biomechanical tests, functional samples were manufactured. A good connection between the additively manufactured Ti6Al4V anchoring structures and NiTi SMA substrate could be observed though crack formation occurring at the transition area between the two materials. These cracks do not propagate during biomechanical testing, nor do they lead to flaking structures. In summary, the hybrid manufacturing of a NiTi SMA substrate with additively manufactured Ti6Al4V structures is suitable for medical implants.

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Annealing Temperature Effect on Superelastic and Cyclic Response of NiTi SMA

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.2243 ◽

2009 ◽

Vol 79-82 ◽

pp. 2243-2246

Author(s):

Li Lan ◽

Alan Kin Tak Lau ◽

Yan Sheng Yin ◽

Liu Tong

Keyword(s):

Phase Transformation ◽

Shape Memory Alloys ◽

Shape Memory ◽

Temperature Effect ◽

Annealing Temperature ◽

Dissipated Energy ◽

Cyclic Response ◽

Niti Sma ◽

Superelastic Behavior ◽

Niti Shape Memory Alloys

To characterize the thermomechanical response, especially the superelastic behavior of NiTi shape memory alloys (SMAs), the DSC and tensile cycle test of NiTi of different annealing temperature have been presented. There’s no remarkable phase transformation peak, however, the stable tensile cycle curve and maximum dissipated energy have been observed at annealing temperature of 673K.

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Shape memory and superelastic behavior of Ti–7.5Nb–4Mo–1Sn alloy

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2011.03.024 ◽

2011 ◽

Vol 32 (8-9) ◽

pp. 4614-4617 ◽

Cited By ~ 28

Author(s):

D.C. Zhang ◽

J.G. Lin ◽

W.J. Jiang ◽

M. Ma ◽

Z.G. Peng

Keyword(s):

Shape Memory ◽

Superelastic Behavior

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EFFECTS OF PARTICLE SIZE AND SINTERING TEMPERATURE ON SUPERELASTICITY BEHAVIOR OF NiTi SHAPE MEMORY ALLOY USING NANOINDENTATION

Surface Review and Letters ◽

10.1142/s0218625x21500244 ◽

2021 ◽

pp. 2150024

Author(s):

C. VELMURUGAN ◽

V. SENTHILKUMAR

Keyword(s):

Particle Size ◽

Shape Memory Alloy ◽

Shape Memory ◽

Sintering Temperature ◽

Niti Alloy ◽

Indentation Load ◽

Niti Shape Memory Alloy ◽

Recovery Ratio ◽

Work Recovery ◽

Niti Sma

The present study investigates the superelasticity properties of spark plasma sintered (SPS) nickel titanium shape memory alloy (NiTi SMA) with the influence of sintering temperature and particle size. The nanoindentation is conducted on the surface of the NiTi SMA at various loads such as 100, 300 and 500[Formula: see text]mN. The nanoindentation technique determines the quantitative results of elasto-plastic properties such as depth recovery in the form of superelasticity, stiffness, hardness and work recovery ratio from load–depth ([Formula: see text]–[Formula: see text]) data during loading and unloading of the indenter. Experimental findings show that the depth and work recovery ratio increases with the decrease of indentation load and particle size. In contrast, increasing the sintering temperature exhibited a better depth and work recovery due to the removal of pores which could enhance the reverse transformation. The contact stiffness is influenced by [Formula: see text] which leads to attain a maximum stiffness at the highest load (500[Formula: see text]mN) and particle size (45[Formula: see text][Formula: see text]m) along with the lowest sintering temperature (700∘C). NiTi alloy exhibited a maximum hardness of 9.46[Formula: see text]GPa when subjected to indent at the lowest load and particle size sintered at 800∘C. The present study reveals a better superelastic behavior in NiTi SMA by reducing the particle size and indentation load associated with the enhancement of sintering temperature.

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Pseudoelasticity of Cu-13.8Al-Ni Alloys Containing V and Nb

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.59.101 ◽

2008 ◽

Vol 59 ◽

pp. 101-107 ◽

Cited By ~ 3

Author(s):

Rodinei Medeiros Gomes ◽

Ana Cris R. Veloso ◽

V.T.L. Buono ◽

Severino Jackson Guedes de Lima ◽

Tadeu Antonio de Azevedo Melo

Keyword(s):

Mechanical Properties ◽

Shape Memory ◽

Shape Recovery ◽

Cold Water ◽

Low Cost ◽

Tensile Tests ◽

Grain Refiner ◽

Good Shape ◽

Potential Applications ◽

Superelastic Behavior

Polycrystalline copper-based shape memory alloys have been of particular interest in relation to Ni-Ti because of their low cost and good shape memory effect. Nevertheless the absence of a pronounced pseudoelasticity effect restricts the number of potential applications. In this work, the influence of Nb and V on the microstructure and the mechanical properties was investigated. Samples of Cu-13.8 Al-Ni containing V and Nb alloy were prepared by induction and solution treated at 850°C and then further quenched into cold water. The addition of Nb and V promotes the formation of precipitates which act as grain refiner and subsequently improve the mechanical properties. The tensile tests were performed at temperatures slightly inferior to Mf and superior to Af, to investigate the shape recovery and pseudoelasticity, respectively. Based on the analyses of the Cu-13,8Al-2Ni-1Nb (wt%) alloy was detected rupture strains greater than 14%, besides observation of the superelasticity of these alloys and quantification of this property by means of cycling, from 0 to strains between 1 and 7%. The studies performed on alloy Cu-13.8Al- 3,5Ni-1V (wt%) made it possible to determine rupture strains in the order of 3% and its superelastic behavior through cycling for deformations between 1 and 3%.

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Fabrication of an Apatite/Collagen Composite Coating on the NiTi Shape Memory Alloy through Electrochemical Deposition and Coating Characterisation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.618-619.319 ◽

2009 ◽

Vol 618-619 ◽

pp. 319-323 ◽

Cited By ~ 5

Author(s):

Parama Chakraborty Banerjee ◽

Tao Sun ◽

Jonathan H.W. Wong ◽

Min Wang

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Composite Coating ◽

Electrochemical Deposition ◽

Room Temperature ◽

Composite Coatings ◽

Deposition Process ◽

Niti Shape Memory Alloy ◽

X Ray ◽

Niti Sma

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.

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A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

BioMed Research International ◽

10.1155/2015/652940 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 10

Author(s):

Christian W. Müller ◽

Ronny Pfeifer ◽

Karen Meier ◽

Sebastian Decker ◽

Janin Reifenrath ◽

...

Keyword(s):

Shape Memory ◽

Induction Heating ◽

Electromagnetic Induction ◽

Plate Osteosynthesis ◽

Bending Stiffness ◽

Niti Sma ◽

Additional Surgery ◽

Rabbit Tibia ◽

Electromagnetic Induction Heating

Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation,µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery.

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Corrosion properties of the superelastic shape memory Ni-Ti alloy for medical implants

MANUFACTURING TECHNOLOGY ◽

10.21062/ujep/x.2013/a/1213-2489/mt/13/3/409 ◽

2013 ◽

Vol 13 (3) ◽

pp. 409-414 ◽

Cited By ~ 4

Author(s):

Dalibor Vojtěch ◽

Jiří Kubásek ◽

Pavel Novák

Keyword(s):

Shape Memory ◽

Ti Alloy ◽

Medical Implants ◽

Corrosion Properties

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An SMA Passive Ankle Foot Orthosis: Design, Modeling, and Experimental Evaluation

Smart Materials Research ◽

10.1155/2014/572094 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Liberty Deberg ◽

Masood Taheri Andani ◽

Milad Hosseinipour ◽

Mohammad Elahinia

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Motion Analysis ◽

Experimental Evaluation ◽

Mechanical Systems ◽

Drop Foot ◽

Ankle Foot Orthosis ◽

New Device ◽

Superelastic Behavior ◽

Foot Orthosis

Shape memory alloys (SMAs) provide compact and effective actuation for a variety of mechanical systems. In this work, the distinguished superelastic behavior of these materials is utilized to develop a passive ankle foot orthosis to address the drop foot disability. Design, modeling, and experimental evaluation of an SMA orthosis employed in an ankle foot orthosis (AFO) are presented in this paper. To evaluate the improvements achieved with this new device, a prototype is fabricated and motion analysis is performed on a drop foot patient. Results are presented to demonstrate the performance of the proposed orthosis.

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Analysis of microscopic bone properties in an osteoporotic sheep model: a combined biomechanics, FE and ToF-SIMS study

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0793 ◽

2019 ◽

Vol 16 (151) ◽

pp. 20180793 ◽

Cited By ~ 3

Author(s):

R. Müller ◽

A. Henss ◽

M. Kampschulte ◽

M. Rohnke ◽

A. C. Langheinrich ◽

...

Keyword(s):

Biomechanical Testing ◽

Tissue Level ◽

Osteoporotic Bone ◽

Compression Tests ◽

Micro Computed Tomography ◽

Deficient Diet ◽

Element Analysis ◽

Sheep Model ◽

Tissue Properties ◽

Bone Properties

The present study deals with the characterization of bone quality in a sheep model of postmenopausal osteoporosis. Sheep were sham operated ( n = 7), ovariectomized ( n = 6), ovariectomized and treated with deficient diet ( n = 8) or ovariectomized, treated with deficient diet and glucocorticoid injections ( n = 7). The focus of the study is on the microscopic properties at tissue level. Microscopic mechanical properties of osteoporotic bone were evaluated by a combination of biomechanical testing and mathematical modelling. Sample stiffness and strength were determined by compression tests and finite-element analysis of stress states was conducted. From this, an averaged microscopic Young’s modulus at tissue level was determined. Trabecular structure as well as mineral and collagen distribution in samples of sheep vertebrae were analysed by micro-computed tomography and time-of-flight secondary ion mass spectrometry. In the osteoporotic sheep model, a disturbed fibril structure in the triple treated group was observed, but bone loss only occurred in form of reduced trabecular number and thickness and cortical decline, while quality of the residual bone was preserved. The preserved bone tissue properties in the osteoporotic sheep model allowed for an estimation of bone strength which behaves similar to the human case.

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