Characterization of Inclusions in VIM/VAR NiTi Alloys

Coda, Alberto; Zilio, Stefano; Norwich, Dennis W.; Sczerzenie, Frank

doi:10.1007/s11665-012-0366-1

Cited by 31 publications

(27 citation statements)

References 5 publications

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“…In all fields of view, no particle with size greater than 39 lm was found, and 1.73 % (area %) of total particles was evaluated. These results are in agreement with the industrial NiTi alloys statistical inclusion [5] confirming that PAM is a suitable melting route for the production of Nitinol for medical devices and surgical tools.…”

Section: Microstructure and Particles Statistical Analysissupporting

confidence: 85%

“…Also, regarding oxide-type inclusions (i.e., Ti 2 NiO x ) Liang and Huang [4] have found that their presence is the main reason for pitting. Coda et al [5] characterized the main types of inclusions of commercial Nitinol produced by VIM and vacuum arc melting (VAR) routes; by means of extreme value statistics, Urbano et al [6] showed that the maximum inclusion dimension in the highly strained volume of a fatigue test contributes to a decrease in the fatigue performance of 0.3-mm-diameter superelastic wires. Morgan et al [7] reported about extra low inclusions content (ELI) alloys appeared to have improved fatigue performances.…”

Section: Introductionmentioning

confidence: 99%

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Plasma Arc Melting (PAM) and Corrosion Resistance of Pure NiTi Shape Memory Alloys

Tuissi

Rondelli

Bassani

2015

Shap. Mem. Superelasticity

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Plasma arc melting (PAM) as a suitable noncontaminating melting route for manufacturing high-quality NiTi alloy was successfully examined. The corrosion resistance of PAM Nitinol was evaluated by both potentiodynamic and potentiostatic tests and compared with lower purity NiTi produced by vacuum induction melting (VIM). For the electro-polished surfaces, excellent corrosion resistance of NiTi comparable with the Ti alloys was found with no pitting up to 800 mV versus saturated calomel electrode in simulated body fluid at 37°C. Potentiostatic results of PAM Nitinol indicate slightly better corrosion resistance than the lower quality VIM alloy.

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Section: Microstructure and Particles Statistical Analysissupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Plasma Arc Melting (PAM) and Corrosion Resistance of Pure NiTi Shape Memory Alloys

Tuissi

Rondelli

Bassani

2015

Shap. Mem. Superelasticity

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“…From previous experimental tests made in the laboratory, similar to those obtained by other authors [5][6][7] it was found that the alloys closest to temperatures of 45ºC -50°C are nitinol alloys.…”

Section: Introductionsupporting

confidence: 82%

“…From the hysteresis graphycs for nitinol transformation temperatures obtained here, in consistence with [7][8][9][10][11][12][13][14][15], it can be argued that there is evidence of transformation temperatures of nitinol to meet the expectations of the medical application.…”

Section: Introductionsupporting

confidence: 52%

Modeling of Shape Memory Alloys for Medical Design in Robotics

Corral-Bustamante¹,

Trevizo²,

Hernandez-Magdaleno³

2015

mst

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This work is about the study of the advanced materials with shape memory alloys (SMAs) for the construction of a medical device for ablation of tumors via radio frequencies, which must be supported by a Cartesian robot of 3 degrees of freedom (RC3GL). The objective focuses on providing equipment to the medical sector to fill the role currently performed manually by the specialist of the state of Chihuahua, Mexico, in patients affected by cancer in organs such as liver, lung, kidney, prostate and breast. In the design of the medical device, it was necessary to control the temperature of transformation between the austenite and matensite phases to which the changes in shape of the SMA is produced in the range of 45ºC to 50ºC. To fulfill the objective, two studies were conducted: i. statistical and ii. experimental by the annealing treatment of SMEs in determined temperature, time and rhythm of heating and cooling, measured by resistivity and dynamo-mechanical (DMTA) techniques that match those of other authors. From the results obtained, the nitinol (Ni wx Ti yz) was selected as the alloy that meets the medical requirements for the successful design of the tumors remover. From the experimental tests for the thermal profile required in the nitinol tip during the ablation process of 8 minutes (modeling and previously simulated which are shown here), made with the medical device adapted to the RC3GL (patent pending), it can be concluded that, the objective of building the medical equipment for removing cancerous tumors in organs is met.

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“…For these reasons, the industrial community has extensively researched the mechanisms that govern fatigue and fracture in nitinol material. We know, for example, that fatigue cracks almost invariably nucleate at microstructural discontinuities at or near surfaces, most notably at non-metallic inclusions and related voids [12,13]. To address this, industry has invested considerable resources to develop high-purity nitinol alloys, with fewer and smaller inclusions.…”

Section: Introductionmentioning

confidence: 99%

The Role of Parent Phase Compliance on the Fatigue Lifetime of Ni–Ti

Bonsignore

Shamini

Duerig

2019

Shap. Mem. Superelasticity

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It has been previously suggested that the fatigue lifetime of superelastic Ni-Ti might be improved if the R-phase were the parent to martensite rather than austenite. This body of work tests that hypothesis in two separate side-by-side fatigue tests both carefully constructed to match the superelastic properties in the two study arms. Both experiments show the R-phase parent to be more durable than the more commonly considered austenitic parent phase. The first experiment considers straight wire specimens fabricated from standard purity material, in a tension-tension fatigue test to 10 7 cycles, at mean strain ranging of 0.5-5.8% and strain amplitudes of 0.15-0.45%. The second experiment considers formed wire specimens in bending fatigue, more representative of realistic medical components, with a maximum mean strain of 1.2%, and maximum strain amplitudes ranging from 0.72 to 1.64%. Compared with the austenitic parent material, the R-phase material tolerated 0.1-0.3% higher strain amplitudes.

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Characterization of Inclusions in VIM/VAR NiTi Alloys

Cited by 31 publications

References 5 publications

Plasma Arc Melting (PAM) and Corrosion Resistance of Pure NiTi Shape Memory Alloys

Plasma Arc Melting (PAM) and Corrosion Resistance of Pure NiTi Shape Memory Alloys

Modeling of Shape Memory Alloys for Medical Design in Robotics

The Role of Parent Phase Compliance on the Fatigue Lifetime of Ni–Ti

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