Characterization of the arcing phenomenon in micro-EDM and its effect on key mechanical properties of medical-grade Nitinol

Mwangi, James Wamai; Bui, Viet D.; Thüsing, Kai; Hahn, S.; Wagner, Martin F.-X.; Schubert, Andreas

doi:10.1016/j.jmatprotec.2019.116334

Cited by 30 publications

(5 citation statements)

References 17 publications

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“…Martensite variants can be twinned (M t ) and de-twinned (M d ). The reversible transformation from austenite to martensite [46] and vice versa results in SMA behavior [49], and it is known that the martensitic transformation can be caused by both temperature and stress [50], which are referred to as SME and pseudoelasticity, respectively [51][52][53]. The essential actuating ability of the NiTi SMA heat engine is a consequence of the pseudoelastic and SME of SMA material.…”

Section: Phase Transformation In Smamentioning

confidence: 99%

A review on Nitinol shape memory alloy heat engines

Abubakar

Wang

2020

Smart Mater. Struct.

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Nitinol (NiTi) shape memory alloy (SMA) heat engine is a very promising candidate application of SMA since its invention, but yet to be put as commercial due to its low efficiency and performance. In this paper, a review of different types of NiTi SMA heat engine is presented. The review is done based on the following headings: conceptual design, constitutive driving model, the performance of the engine, and engine limitations. Factors like temperature, cooling rate, size of NiTi SMA element, and the stretch ratio of NiTi SMA spring were identified as determinants of final output power and efficiency of SMA heat engines. It is found that a crankshaft NiTi SMA heat engine produced the highest power output value of 4 watt, an unsynchronized pulley NiTi SMA heat engine with 11.3% of engine efficiency has the highest engine performance so far recorded. Some engine's drawbacks like an improper driving model, drag loss, backsliding were identified as the major problem affecting the engine performance, and which, if solved, will increase the overall performance and efficiency for future development toward its commercialization.

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Section: Phase Transformation In Smamentioning

confidence: 99%

A review on Nitinol shape memory alloy heat engines

Abubakar

Wang

2020

Smart Mater. Struct.

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“…Effect on mechanical properties of Nitinol (medical grade) and characterization (arcing phenomena) in micro-EDM has been reported by Mwangi et al (2020). They have reported that the three peak-transformation behaviour arcing phenomena will play a vital role, and thermal damage caused by arcing enhances residual strain, minimizes elongation to failure, machining accuracy, and lower and upper plateau stresses.…”

Section: Introductionmentioning

confidence: 99%

Multi-response optimization of EDM drilling parameters of the Nitinol SMA

2021

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The demand for Nitinol (SMA) is increasing rapidly for various applications. With the aim of optimum control parameters of EDM, 46 experiments completed on six specimens of 6.156 mm thickness using Sparkonix EDM drill machine. Current (I), voltage (V), charging-time (TON), discharging-time (TOFF), and dielectric pressure (DP) were taken as input control parameters. Single-indexed optimization of material removal rate (MRR), tool-wear rate (TWR), and degree of tapperness (DoT) are evaluated using gray relational grade (GRG). Individual control-parameter contributions are evaluated using Taguchi and ANOVA. The obtained optimal input control parameters were used for the confirmation experiment, and the obtained result gives good agreement to it. V and TON are found as the most significant parameters. Maximum and minimum values of MRR, TWR, and DoT have been recorded as 0.0277 & 0.0074 g/min, 0.0177 & 0.0033 g/min, and 0.032 & 0.01 radians respectively. MRR, TWR, and DoT improved by 49.1, 4.5, and 43.3 %, respectively.

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“…Recent studies show that standard machining techniques for modern engineering materials, including Udimet 720, are often difficult owing to higher strength, hardness, and considerable heat generation [13]. Furthermore, conventional machining reduces the tool life owing to lower heat conductivity [14]. Another limitation of conventional machining for Udimet 720 is the poor surface finish, poor dimensional accuracy, noise operation, and difficulty in producing complex shape geometries.…”

Section: Introductionmentioning

confidence: 99%

Effect of Multi-walled carbon nanotubes on the performance evaluation of Nickel-based super-alloy–Udimet 720 machined using WEDM process

Chaudhari¹,

Ayesta

Doshi³

et al. 2022

Preprint

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The diverse capabilities of nickel-based super-alloy (Udimet 720), like robust mechanical strength, ductility, resistance to excessive temperature deformation, and advanced corrosion and oxidation resistance, make it suitable for use in multiple applications. These super-alloys are identified as extremely difficult materials for machining to meet feature and manufacturing requirements. In the present work, we demonstrated the machining of Udimet 720 by employing the wire-electrical discharge machining (WEDM) technique. Pulse-on-time (Ton), Pulse-off-time (Toff), current, and MWCNT amount were preferred as input variables. The effect of selected design variables was studied on material removal rate (MRR), surface roughness (SR), and recast layer thickness (RLT). Box Behnken design was utilized to design an experimental matrix. For statistical analysis, analysis of variance (ANOVA) was employed. From ANOVA, the current had the highest contributor with 35.85% to affect MRR, while MWCNT amount was found to be the highest contributor for deciding the values of both SR and RLT with contributions of 42.66% and 40.07%, respectively. The addition of MWCNT at 1 g/L has substantially improved MRR from 0.8546 g/min to 1.2199 g/min, SR reduced from 5.88 µm to 2.98 µm, and reduction in RLT from 17.8 µm to 11.61 µm. The passing vehicle search (PVS) algorithm was implemented, and the results of single-objective optimization presented the largest MRR of 1.8883 g/min, least SR of 1.89 µm, and least RLT of 9.70 µm. Additionally, a set of non-dominated solutions was obtained through Pareto optimal fronts. A small acceptable deviation was detected among the actual and forecasted results from PVS algorithm. It clearly reveals the acceptance of the PVS technique in the present study for Udimet 720. Lastly, the significance of MWCNT amount on surface textures was revealed by employing scanning electron microscopy (SEM).

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Characterization of the arcing phenomenon in micro-EDM and its effect on key mechanical properties of medical-grade Nitinol

Cited by 30 publications

References 17 publications

A review on Nitinol shape memory alloy heat engines

A review on Nitinol shape memory alloy heat engines

Multi-response optimization of EDM drilling parameters of the Nitinol SMA

Effect of Multi-walled carbon nanotubes on the performance evaluation of Nickel-based super-alloy–Udimet 720 machined using WEDM process

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