Manufacturing and processing of NiTi implants: A review

Elahinia, Mohammad; Hashemi, Mahdi; Tabesh, Majid; Bhaduri, Sarit B.

doi:10.1016/j.pmatsci.2011.11.001

Cited by 869 publications

(471 citation statements)

References 79 publications

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“…Ni-Ti alloys have found applications in many areas of engineering ranging from aerospace to biomedical [1]. This is due to their unique properties such as superelasticity, biocompatibility, shape memory effect and excellent corrosion resistance which have made them a material of choice for the manufacture of vascular stents and other medical devices used for bone and tissue replacement in the human body [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…Compared to additive manufacturing (AM) techniques, such as selective laser melting (SLM) and direct laser metal deposition (DLMD), the aforementioned techniques are slower and limited in design freedom. Through AM, components with complex geometries without a use of cutting tools or fixtures can easily be built [1]. Also, the microstructure, hence, the properties of the components built using AM techniques can be tailored to the required design intent by controlling the processing parameters [5].…”

Section: Introductionmentioning

confidence: 99%

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Functionally graded Ni-Ti microstructures synthesised in process by direct laser metal deposition

Abioye

Farayibi

Kinnel

et al. 2015

Int J Adv Manuf Technol

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The fabrication of biomedical devices using Ni-Ti compositions is limited to conventional techniques and the use of near equiatomic pre-alloyed Ni and Ti powders. In this study, functionally graded walls and cylinder built by concurrent feeding of Ni powder and commercially pure (CP) Ti wire using direct laser metal deposition technique are presented. The built structures consist of CP Ti wire-deposited layers and Ni-Ti layers of varying Ni composition. The microstructures of the built Ni-Ti structures including phase identification, phase compositions and area fractions of the phases present at various processing parameters were determined using a combination of scanning electron microscopy/ energy dispersive X-ray spectroscopy, X-ray diffractometry and image processing software. Vickers microhardness test was conducted on the deposited structures. It was found that the Ni-Ti layers comprise of NiTi and NiTi 2 phases. The area fraction of the NiTi phase increases, whereas NiTi 2 decreases with increasing the Ni powder feed rate. Ni-Ti layers with higher area fractions of NiTi 2 phase are found to be harder with a maximum of 513 HV 0.3 found in this study. The micro-hardness of Ni-Ti layers is, by at least a factor of 1.5, higher than the CP Ti wire laser-deposited layers.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Functionally graded Ni-Ti microstructures synthesised in process by direct laser metal deposition

Abioye

Farayibi

Kinnel

et al. 2015

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…NiTi shape memory alloys have been extensively applied in mechanical, aerospace and medical industries, due to their excellent shape memory effect, good corrosion resistance, and superior mechanical properties and biocompatibility [1,2]. As the medical implant materials, the high elastic modulus of NiTi alloys can't match well with the low elastic modulus of human skeleton bones, which will influence the load transfer between them, causing "stress shielding" [3].…”

Section: Introductionmentioning

confidence: 99%

Effect of soaking time on the preparation of porous NiTi alloy during fields-activated micro-sintering and forming technology

Zhao

Yang

Liu

et al. 2015

MATEC Web of Conferences

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Abstract. In this study, porous NiTi alloys have been successfully produced by fieldsactivated micro-sintering and forming technology under the pressure of 75 MPa at 1100 • C. The effects of soaking time on the porous NiTi alloys were investigated by analysing porosities, microstructures, and phase compositions of the produced alloys. The porosities of 41.2%, 38.8% and 47.2% are achieved at the soaking time of 2 min, 6 min and 10 min respectively. SEM examinations show that the pore size is varied with the soaking time and X-ray diffraction studies reveal that the main phases are NiTi, Ni 3 Ti and NiTi 2 .

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“…For their wider usage development of easier and more effective ways of metalworking is necessary. Melting, casting, metalworking, and heat treatments of NiTi shape memory alloys strongly influence their microstructure, phase transformations, mechanical, and shape memory properties (Ref 11,12). Due to the fact that molten titanium is highly reactive, the NiTi alloys must be melted in high vacuum or in an inert gas atmosphere (Ref 12,13).…”

Section: Introductionmentioning

confidence: 99%

Microstructure, Phase Transformations, and Properties of Hot-Extruded Ni-Rich NiTi Shape Memory Alloy

Lekston

Zubko

Prusik

et al. 2014

J. of Materi Eng and Perform

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Processing of NiTi shape memory alloys strongly influences their microstructure, phase transformations, mechanical, and shape memory properties. Hot forging, hot swaging, or hot rolling are efficient techniques for obtaining the desired shape, but during multiple operations the material must be heated and worked in the temperature range from 700 to 900°C. During these processes, intense oxidation takes place. In order to reduce it, the hot-pack working is applied. The hot extrusion is more effective for reduction of ingot, billet, and rod diameters than hot forging, hot swaging, or hot rolling. Also, during hot extrusion the material surface undergoes considerably less oxidation. In the present work, results of the characterization by differential scanning calorimetry, low-temperature x-ray powder diffraction, and three-point bending and free recovery ASTM F2082-06 tests of the samples after hot direct extrusion and heat treatment are presented. The obtained alloy after hot direct extrusion exhibits desired shape memory effect. The phase transformations during cooling and heating cycle occur with the presence of the R phase. The range of the characteristic temperatures for the obtained material gives possibility for further medical applications. After annealing at 400 and 500°C, the characteristic temperatures shift to higher values.

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Manufacturing and processing of NiTi implants: A review

Cited by 869 publications

References 79 publications

Functionally graded Ni-Ti microstructures synthesised in process by direct laser metal deposition

Functionally graded Ni-Ti microstructures synthesised in process by direct laser metal deposition

Effect of soaking time on the preparation of porous NiTi alloy during fields-activated micro-sintering and forming technology

Microstructure, Phase Transformations, and Properties of Hot-Extruded Ni-Rich NiTi Shape Memory Alloy

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