Influence of Micro-EDM on the Phase Transformation Behaviour of Medical-Grade Nitinol

Shape Memory and Superelasticity volume 4, pages 450–461 (2018)Cite this article

Abstract

Most nitinol medical applications are hinged on its superelasticity and shape memory—two unique properties that are dependent on nitinol’s phase transformation between a martensitic phase and an austenitic phase. Since these transformations are thermomechanical in nature, establishing the influence of thermal processing on nitinol’s phase-transformation behaviour is vital as this can help in predicting changes and/or tuning its mechanical properties to fit specific applications. This study uses differential scanning calorimetry to investigate the influence of micro-electrical discharge machining (micro-EDM) on nitinol’s phase-transformation behaviour. For conclusive analysis, a relatively athermal Jet-ECM process is used as a reference for the as-received material, whereas Laser, a more commercially established medical-grade nitinol machining process, is used to provide comparative analytical aid. From the results, it can be clearly shown that high discharge energies in micro-EDM do indeed have the potential to significantly alter nitinol’s transformation behaviour, including reducing thermal hysteresis and resulting in the occurrence of an unusual three-peak phenomenon in the endothermic reverse transformation on heating.

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Abbreviations

\(A_{\text {f}}\) :

Austenite finish if one austenite phase exists (\(^{\circ }{\text {C}}\))

\(A_{{\text {f}}1}\) :

Austenite finish for the first austenitic phase (\(^{\circ }{\text {C}}\))

\(A_{{\text {f}}2}\) :

Austenite finish for the second austenitic phase (\(^{\circ }{\text {C}}\))

\(A_{\text {p}}\) :

Austenite peak if one austenite phase exists (\(^{\circ }{\text {C}}\))

\({A}_{{\text {p}}1}\) :

Austenite peak for the first austenitic phase (\(^{\circ }{\text {C}}\))

\(A_{{\text {p}}2}\) :

Austenite peak for the second austenitic phase (\(^{\circ }{\text {C}}\))

\(A_{\text {s}}\) :

Austenite start if one austenite phase exists (\(^{\circ }{\text {C}}\))

\(A_{{\text {s}}1}\) :

Austenite start for the first austenitic phase (\(^{\circ }{\text {C}}\))

\(A_{{\text {s}}2}\) :

Austenite start for the second austenitic phase (\(^{\circ }{\text {C}}\))

\(M_{\text {f}}\) :

Martenite finish if one martensite phase exists (\(^{\circ }{\text {C}}\))

\(M_{{\text {f}}1}\) :

Martenite finish for the first martensitic phase (\(^{\circ }{\text {C}}\))

\(M_{{\text {f}}2}\) :

Martenite finish for the second martensitic phase (\(^{\circ }{\text {C}}\))

\(M_{\text {p}}\) :

Martenite peak if one martensite phase exists (\(^{\circ }{\text {C}}\))

\(M_{{\text {p}}1}\) :

Martenite peak for the first martensitic phase (\(^{\circ }{\text {C}}\))

\(M_{{\text {p}}2}\) :

Martenite peak for the second martensitic phase (\(^{\circ }{\text {C}}\)]

\(M_{\text {s}}\) :

Martenite start if one martensite phase exists (\(^{\circ }{\text {C}}\))

\(M_{{\text {s}}1}\) :

Martenite start for the first martensitic phase (\(^{\circ }{\text {C}}\))

\(M_{{\text {s}}2}\) :

Martenite start for the second martensitic phase (\(^{\circ }{\text {C}}\))

\(R_{\text {cf}}\) :

R-phase finish while cooling (\(^{\circ }{\text {C}}\))

\(R_{\text {cp}}\) :

R-phase peak while cooling (\(^{\circ }{\text {C}}\))

\(R_{\text {cs}}\) :

R-phase start while cooling (\(^{\circ }{\text {C}}\))

\(R_{\text {hf}}\) :

R-phase finish while heating (\(^{\circ }{\text {C}}\))

\(R_{\text {hp}}\) :

R-phase peak while heating (\(^{\circ }{\text {C}}\))

\(R_{\text {hs}}\) :

R-phase start while heating (\(^{\circ }{\text {C}}\))

\(\Delta H\) :

Transformation enthalpy per unit volume (J/kg)

\(\Delta H_{\text {A}}\) :

Enthalpy if one austenite phase exists (J/kg)

\(\Delta H_{{\text {A}}1}\) :

Enthalpy for the first austenitic phase (J/kg)

\(\Delta H_{{\text {A}}2}\) :

Enthalpy for the second austenitic phase (J/kg)

\(\Delta H_{\text {M}}\) :

Martensite enthalpy (J/kg)

\(\Delta H_{\text {RC}}\) :

R-phase enthalpy on cooling (J/kg)

\(\Delta H_{\text {RH}}\) :

R-phase enthalpy on heating (J/kg)

\(i_{\text {e}}\) :

Discharge current (A)

T :

Test temperature (\(^{\circ }{\text {C}}\))

\(t_{\text {e}}\) :

Pulse duration (s)

\(u_{\text {e}}\) :

Discharge voltage (V)

\(E_{\text {d}}\) :

Discharge energy (J)

\(\sigma \) :

Stress (N/m\(^{2}\))

\(\epsilon \) :

Strain

References

  1. 1.

    Kapoor D (2017) Nitinol for medical applications: a brief introduction to the properties and processing of nickel titanium shape memory alloys and their use in stents. Johns Matthey Technol Rev 61(1):66

    Article  Google Scholar 

  2. 2.

    Yildiz C, Kucukyildirim B, Akdogan Eker A (2014) Effect of cold deformation to transformation temperatures of Ni-Ti shape memory alloys. Arch Mater Sci Eng 66(1):37–44

    Google Scholar 

  3. 3.

    Pelton AR, Dicello J, Miyazaki S (2000) Optimisation of processing and properties of medical grade Nitinol wire. Minim Invasive Ther Allied Technol 9(2):107

    Article  Google Scholar 

  4. 4.

    Bannayan M (2015) Grinding and guidewires: manufacturing for minimally invasive surgery. http://www.medicaldesignbriefs.com/component/content/article/mdb/features/23536

  5. 5.

    Duerig TW, Pelton A, Stöckel D (1999) An overview of nitinol medical applications. Mater Sci Eng A 273–275:149. https://doi.org/10.1016/S0921-5093(99)00294-4

    Article  Google Scholar 

  6. 6.

    Weafer FM, Bruzzi MS (2014) Inuence of microstructure on the performance of nitinol: a computational analysis. J Mater Eng Perform 23(7):2539. https://doi.org/10.1007/s11665-014-1017-5

    Article  Google Scholar 

  7. 7.

    Chen W, Song B (2006) Temperature dependence of a NiTi shape memory alloy’s superelastic behavior at a high strain rate. J Mech Mater Struct 1(2):339–356

    Article  Google Scholar 

  8. 8.

    Daly S, Ravichandran G, Bhattacharya K (2007) Stress-induced martensitic phase transformation in thin sheets of Nitinol. Acta Mater 55(10):3593. https://doi.org/10.1016/j.actamat.2007.02.011

    Article  Google Scholar 

  9. 9.

    Laureanda C (2008) One way and two way-shape memory effect: thermo-mechanical characterization of Ni--Ti wires. Ph.D. thesis, Universitá degli Studi di Pavia

  10. 10.

    Mizar SP (2005) Thermomechanical characterization of NiTiNOL and NiTiNOL based structures using ACES methodology. PhD Thesis

  11. 11.

    Brinson LC (1993) One-dimensional constitutive behavior of shape memory alloys: thermomechanical derivation with non-constant material functions and redefined martensite internal variable. J Intell Mater Syst Struct 4(2):229. https://doi.org/10.1177/1045389X9300400213

    Article  Google Scholar 

  12. 12.

    Bourne N (2016) Unexpected twins. Physics 9(February):17. https://doi.org/10.1103/Physics.9.19

    Google Scholar 

  13. 13.

    Wagner MF, Dey SR, Gugel H, Frenzel J, Somsen C, Eggeler G (2010) Effect of low-temperature precipitation on the transformation characteristics of Ni-rich NiTi shape memory alloys during thermal cycling. Intermetallics 18(6):1172. https://doi.org/10.1016/j.intermet.2010.02.048

    Article  Google Scholar 

  14. 14.

    Otsuka K, Ren X (2005) Physical metallurgy of Ti-Ni-based shape memory alloys. Prog Mater Sci 50(5):511. https://doi.org/10.1016/j.pmatsci.2004.10.001

    Article  Google Scholar 

  15. 15.

    Nishida M, Wayman CM, Honma T (1986) Precipitation processes in near-equiatomic TiNi shape memory alloys. Metall Trans A 17(9):1505

    Article  Google Scholar 

  16. 16.

    Johnson Matthey medical component. Nitinol specification guidelines. http://jmmedical.com/resources/120/Nitinol-Specification-Guidelines.html

  17. 17.

    Frenzel J, Wieczorek A, Opahle I, Maaß B, Drautz R, Eggeler G (2015) On the effect of alloy composition on martensite start temperatures and latent heats in Ni-Ti-based shape memory alloys. Acta Mater 90:213. https://doi.org/10.1016/j.actamat.2015.02.029

    Article  Google Scholar 

  18. 18.

    Mwangi JW, Nguyen LT, Bui VD, Berger T, Zeidler H, Schubert A (2018) Nitinol manufacturing and micromachining: a review of processes and their suitability in processing medical-grade nitinol. J Manuf Process (in print)

  19. 19.

    ASTM F2063-12 (2012) Standard specification for wrought nickel-titanium shape memory alloys for medical devices and surgical implants. ASTM International, West Conshohocken

    Google Scholar 

  20. 20.

    Liu Y, Blanc M, Tan G, Kim JI, Miyazaki S (2006) Effect of ageing on the transformation behaviour of Ti–49.5 at.% Ni. Mater Sci Eng A 438—-440(Spec. Iss):617. https://doi.org/10.1016/j.msea.2006.02.165

    Article  Google Scholar 

  21. 21.

    Treppmann D (1997) Thermomechanische Behandlung von NiTi: (mit Lösungsansätzen für Qualitätssicherung und Normung von Formgedächtnislegierungen). Fortschritt-Berichte VDI: Reihe 5, Grund- und Werkstoffe (VDI-Verlag)

  22. 22.

    Duerig TW, Pelton AR, Bhattacharya K (2017) The measurement and interpretation of transformation temperatures in nitinol, shape memory and superelasticity. https://doi.org/10.1007/s40830-017-0133-0

  23. 23.

    Spini TS, Valarelli FP, Cançado RH, de Freitas KMS, Villarinho DJ (2014) Transition temperature range of thermally activated nickel-titanium archwires. J Appl Oral Sci 22(2):109. https://doi.org/10.1590/1678-775720130133

    Article  Google Scholar 

  24. 24.

    Wada K (2016) Partial transformation and the two-way shape recovery characteristics. J Mater Sci Eng 5(4):1. https://doi.org/10.4172/2169-0022.1000262

    Google Scholar 

  25. 25.

    Duerig TW, Bhattacharya K (2015) The influence of the R-phase on the superelastic behavior of NiTi. Shape Mem Superelast 1(2):153. https://doi.org/10.1007/s40830-015-0013-4

    Article  Google Scholar 

  26. 26.

    Wang X, Li C, Verlinden B, Van Humbeeck J (2013) Effect of grain size on aging microstructure as reflected in the transformation behavior of a low-temperature aged Ti–50.8 at.% Ni alloy. Scr Mater 69(7):545. https://doi.org/10.1016/j.scriptamat.2013.06.023

    Article  Google Scholar 

  27. 27.

    Shamimi A, Amin-Ahmadi B, Stebner A, Duerig T (2018) The effect of low temperature aging and the evolution of R-phase in Ni-Rich NiTi. Shape Memory and Superelasticity. https://doi.org/10.1007/s40830-018-0193-9

    Google Scholar 

  28. 28.

    Nematzadeh F, Sadrnezhaad SK (2012) Effects of material properties on mechanical performance of Nitinol stent designed for femoral artery: finite element analysis. Sci Iran 19(6):1564. https://doi.org/10.1016/j.scient.2012.10.024

    Article  Google Scholar 

  29. 29.

    Patel M, Plumley D, Bouthot R, Proft J (2006) The effects of varying active Af temperatures on the fatigue properties of nitinol wire. In: ASM material and processes for medical devices conference and exposition (MPMD), vol 251, p 148

  30. 30.

    Tuissi A, Coduri M, Biffi CA (2017) Laser shape setting of superelastic nitinol wires: functional properties and microstructure. Funct Mater Lett 10:1740008

    Article  Google Scholar 

Download references

Acknowledgements

The authors are thankful to the German Academic Exchange Service (DAAD), Technische Universitaet Chemnitz, and NACOSTI, Kenya for facilitating this research. Special thanks are offered to Johnson Matthey Medical Components Company for providing the nitinol sheet, and to Fraunhofer IWU Dresden and Chemnitz for the DSC measurements and SEM measurements, respectively.

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Affiliations

  1. Professorship of Micromanufacturing Technology, Chemnitz University of Technology, Reichenhainer Strasse 70, 09107, Chemnitz, Germany

    James Wamai Mwangi, Viet Duc Bui, Matin Yahyavi Zanjani & Andreas Schubert

  2. Fraunhofer Institute for Machine Tools and Forming Technology, Nöthnitzer Str. 44, 01187, Dresden, Germany

    Linda Weisheit

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  1. James Wamai Mwangi
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Correspondence to James Wamai Mwangi.

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Mwangi, J.W., Weisheit, L., Bui, V.D. et al. Influence of Micro-EDM on the Phase Transformation Behaviour of Medical-Grade Nitinol. Shap. Mem. Superelasticity 4, 450–461 (2018). https://doi.org/10.1007/s40830-018-00195-1

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Keywords

  • Micro-EDM
  • Nitinol
  • Phase-transformation behaviour
  • Shape memory
  • Superelasticity
  • Differential scanning calorimetry
  • Laser
  • Jet-ECM