Biological and Corrosion Evaluation of In Situ Alloyed NiTi Fabricated through Laser Powder Bed Fusion (LPBF)

Chmielewska, Agnieszka; Dobkowska, Anna; Kijeńska‐Gawrońska, Ewa; Jakubczak, Michał; Krawczyńska, Agnieszka; Choińska, Emilia; Jastrzębska, Agnieszka; Dean, David; Wysocki, Bartłomiej; Święszkowski, Wojciech

doi:10.3390/ijms222413209

Cited by 7 publications

(4 citation statements)

References 60 publications

(64 reference statements)

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“…The XRD phase analysis did not indicate the presence of TiO 2 . However, it has been shown in our previous study that the thin layer of TiO 2 was found on the material's surface by X-ray photoelectron spectroscopy (XPS) [48]. Since the peaks corresponding to NiTi (B19 ), NiTi 2 and Ni 2 Ti 4 O overlap each other the XRD technique cannot be used alone to determine which phase is present in the studied alloy.…”

Section: Third Heat Treatment-ht3mentioning

confidence: 95%

Heat Treatment of NiTi Alloys Fabricated Using Laser Powder Bed Fusion (LPBF) from Elementally Blended Powders

et al. 2022

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The use of elemental metallic powders and in situ alloying in additive manufacturing (AM) is of industrial relevance as it offers the required flexibility to tailor the batch powder composition. This solution has been applied to the AM manufacturing of nickel-titanium (NiTi) shape memory alloy components. In this work, we show that laser powder bed fusion (LPBF) can be used to create a Ni55.7Ti44.3 alloyed component, but that the chemical composition of the build has a large heterogeneity. To solve this problem three different annealing heat treatments were designed, and the resulting porosity, microstructural homogeneity, and phase formation was investigated. The heat treatments were found to improve the alloy’s chemical and phase homogeneity, but the brittle NiTi2 phase was found to be stabilized by the 0.54 wt.% of oxygen present in all fabricated samples. As a consequence, a Ni2Ti4O phase was formed and was confirmed by transmission electron microscopy (TEM) observation. This study showed that pore formation in in situ alloyed NiTi can be controlled via heat treatment. Moreover, we have shown that the two-step heat treatment is a promising method to homogenise the chemical and phase composition of in situ alloyed NiTi powder fabricated by LPBF.

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Section: Third Heat Treatment-ht3mentioning

confidence: 95%

Heat Treatment of NiTi Alloys Fabricated Using Laser Powder Bed Fusion (LPBF) from Elementally Blended Powders

et al. 2022

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“…Here, the corrosion product grows from pit to pit due to the absorption of oxygen by the elemental Ti to form the TiO 2 and TiO 3 product. [32][33][34] In comparison with different corrosion products, Ti oxide requires less driving energy to form a stable product at room temperature. In the region of the NiTi phase, there is no effect of corrosion observed.…”

Section: Morphology Analysis Before and After The Cryo Treatmentmentioning

confidence: 99%

Cryo treatment and corrosion studies of nickel-titanium shape-memory alloy

Vishwanatha

Saxena

Pramanik

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part E:

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Nickel (Ni)-titanium (Ti) shape-memory alloy (SMA) is a functional material that has received a higher demand in aerospace industries, biomedical industries, actuator, and sensor industries owing to the property of superelasticity and shape memory effect. In addition, SMAs offer better mechanical and corrosion-resistant properties. In this current work, cryo treatment of NiTi alloy has been carried out to investigate the change in the properties. NiTi SMA prepared by powder metallurgy are cryo treated for 12 hours to 48 hours. Further, a corrosion study has been performed on the cryo-treated NiTi samples with the variation in corrosion time to know the effect on the morphology and the hardness. It is found that cryo-treated NiTi shows higher resistance to corrosion than the non-treated sample. The present work is an attempt to find out the effect of cryo treatment on the hardness and corrosion behavior of NiTi SMA. In the scanning electron microscope (SEM) analysis, it is observed that with the increase in cryo treatment time, NiTi (martensite) phase increases. Similar phases are present in both untreated and cryo-treated NiTi pellets. Out of all cryo-treated NiTi pellets, 24 hours cryo-treated NiTi has a lower percentage of corroded area with an increase in the corrosion exposure time. Corrosion preferentially starts at the pit area and progresses toward the Ti-rich area. The hardness value increased for 48 hours cryo-treated sample when compared with other cryo-treated and untreated NiTi pellets.

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“…One example is the increasing use of 2 additive technologies to produce components in NiTi alloy (nickel-titanium alloys-Nitinol), characterised by unique thermo-mechanical properties. 3D printing of NiTi alloy components opens the way to more advanced applications in various industries and biomedical engineering [10][11][12][13][14]. However, there are also technical challenges associated with 3D printing of NiTi alloys, such as control of the microstructure and mechanical properties, which require further research and technological development.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Ageing on Phase Transformations and Nanoindentation Behaviour in Ni-Rich NiTi Alloys

Ratajski,

Bałasz,

Mydłowska

et al. 2024

Preprint

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In the article, the results of research on a NiTi alloy with a high nickel content (51.7 at.%), produced using the additive technology SLM method and subjected to isothermal aging after so-lution annealing, are presented. The study involved the determination of the sequence of phase transformations occurring using differential scanning calorimetry (DSC), and the determination of the temperature range of these transformations. In parallel, the phase composition was determined using the XRD method; hardness and the Young’s modulus were also determined. The analysis of the DSC results obtained indicates the following characteristic features of the NiTi alloy, which change with ageing time: (1) during cooling (from +1500C to -500C), the type of transformation changes from a one-step transformation after solution annealing to a two-step transformation after the ageing process over 1, 20 and 100 hours at 500°C; (2) during heating (from -500C to +1500C) for all the samples, regardless of the ageing time, only a one-step transformation from martensite M(B19’) to austenite A(B2) is observed; (3) the temperature at which the transformation starts increases with the ageing time, (4) the width of the total temperature range of the transformation M(B19’)  A(B2) during heating changes from large (∆T=49,7°C), after solution annealing, to narrow (∆T=19.3°C and ∆T=17.9°C after 20 h and 100 h of ageing) and, most importantly, (5) a comparison with literature data shows that, irrespective of the composition of the NiTi alloy and the manufacturing technology of the alloy samples (regardless of the fact whether this was traditional or additive technology), a sufficiently long ageing process period leads to the occurrence of the martensite  austenite transformation in the same temperature range.

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Biological and Corrosion Evaluation of In Situ Alloyed NiTi Fabricated through Laser Powder Bed Fusion (LPBF)

Cited by 7 publications

References 60 publications

Heat Treatment of NiTi Alloys Fabricated Using Laser Powder Bed Fusion (LPBF) from Elementally Blended Powders

Heat Treatment of NiTi Alloys Fabricated Using Laser Powder Bed Fusion (LPBF) from Elementally Blended Powders

Cryo treatment and corrosion studies of nickel-titanium shape-memory alloy

The Effect of Ageing on Phase Transformations and Nanoindentation Behaviour in Ni-Rich NiTi Alloys

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