SFB 459:  Shape Memory Technology - Fundamentals, Engineering Design and Applications, Processing and Manufacturing

Final Report Abstract

The shape memory effect (SME) fascinates by the property that some materials return to a prefixed shape from any arbitrary bent form just by heating. This phenomenon holds a great potential for actuating, heat transfer and applications, where e. g. a rubber-like behavior of a metal is helpful. The research center (SFB) 459 was founded to solve a variety of scientific and technical problems which prevented a widespread application of shape memory technology. Over the 12 years of funding by the DFG and the state of NRW, important and internationally considerable progress has been made. Today, this enables, for example, a more cost-effective production of medical products with SME with exactly predictable properties. The SFB 459 could clarify the mechanisms at the atomic level, by which the FGE gets worse after repeated application. As a result, shape memory alloys could be produced with much better fatigue behavior. In this regard, significant progress has been achieved in the smelting metallurgy. A notable reduction in undesired phases was also achieved by modification of the previous procedure, which not only has greatly increased the life of shape memory components but also has eliminated the so far unknown cause for an unwanted multistage switching of FGE in applications. Furthermore, the powder metallurgical production of shape memory components by injection molding or laser sintering was brought to a usable stage. Hereby, much more complex components with a shape memory effect can be produced with lower material costs. The welding of shape memory alloys with other materials has also been successfully tested. Numerous material data and construction principles for the practical design of components were found. The developed material models in SFB 459 allow for the pre-calculation of the properties of complex shape memory components. Elaborate investigations in the SFB 459 on the corrosion and biocompatibility of Ni-Ti shape memory alloys justify their use, in spite of the nickel content, as implant materials which are qualified for the minimally invasive surgery because of their special rubber-like behavior.

Publications

• Creep Behavior of NiTi Shape Memory Alloys and the Effect of Pre-Creep on Martensitic Phase Transformation, in: Materials Science Forum (Trans. Tech. Publications, Switzerland), 327-328 (2000) pp. 183-186
  G.F. Eggeler, K. Neuking, A. Dlouhy, E. Kobus
  
• Damping of Superelastic NiTi-Alloys under Torsional Loading; Shape Memory Materials and its Applications, Proceedings of the International Conference on Shape Memory and Superelastic Technologies and Shape Memory Materials SMST-SMM 2001,Trans Tech Publications Ltd, Uetikon/Zürich (2001)
  W. Predki, M. Klönne
  
• Influence of precipitation and dislocation substructure on phase transformation temperatures in a Ni-rich NiTi shape memory alloy, J. Phys. IV France, 11 (2001) Pr8 pp. 529-534
  J. K. Allafi, A. Dlouhy, K. Neuking, G. Eggeler
  
• Microstructure and Tensile Properties of two Binary NiTi-Alloys, Scripta mater., 44 (2001) pp. 171-178)
  E. Hornbogen, V. Mertinger, D. Wurzel
  
• Damping of Superelastic NiTi-Alloys under Torsional Loading, SMST 2001, Materials Science Forum, 394-395 (2002) pp. 115-118
  Predki, M. Kloenne
  
• Easy assessment of the biocompatibility of Ni-Ti alloys by in vitro cell culture experiments on a functionally graded Ni-NiTi-Ti material, Biomaterials, 23 (2002) pp. 4549-4555
  D. Bogdanski, M. Köller, D. Müller, G. Muhr, M. Bram, H. P. Buchkremer, D. Stöver, J. Choi, M. Epple
  
• Fertigungsgerechte, wissensbasierte Konstruktion in der Formgedächtnistechnik, Konstruktion, 10 (2002) pp. 59-62
  E. Welp, J. Breidert, K. Weinert, M. Buschka, V. Petzoldt
  
• Neutron diffraction phase analysis during thermal cycling of a Ni-rich NiTi shape memory alloy using the Rietveld method, Scripta Mater., 46 (2002) pp. 543-548
  H. Sitepu, W.W. Schmahl, J. Khalil Allafi, G. Eggeler, A. Dlouhy, D.M. Többens, M. Tovar
  
• Powder Metallurgical Fabrication Processes for NiTi Shape Memory Alloy Parts, Mater. Sci. Eng. A, 337 (2002) pp. 254-263
  M. Bram, A. Ahmad-Khanlou, A. Heckmann, B. Fuchs, H. Buchkremer, D. Stöver
  
• Texture and Quantitative Phase Analysis of Aged Ni-Rich NiTi using X-Ray and Neutron Diffractions, SMST 2001, Materials Science Forum, 394-395 (2002) pp. 237-240
  H. Sitepu, W.W. Schmahl, J. Khalil Allafi, G. Eggeler, T. Reinecke, H.G. Brokmeier, M. Tovar, D.M. Többens
  
• The mechanism of multiple step martensitic transformations in Ni-rich NiTi shape memory alloys, Acta Mater., 50 (2002) pp. 793-803
  J. Khalil Allafi, X. Ren, G. Eggeler
  
• Composites of different shape memory alloys and polymers for complex actuator motion, J. Phys. IV, 112 (2003) pp. 1163-1168
  B. Winzek, T. Sterzl, H. Rumpf, E. Quandt
  
• Crack initiation and propagation in 50.9 at.% Ni-Ti pseudo elastic shape-memory wires in bending-rotation fatigue, Met. Mat. Trans. A, 34 (2003) pp. 2847-2860
  T. Sawaguchi, G. Kausträter, A. Yawny, M. Wagner, G. Eggeler
  
• Fatigue of orthodontic Nickel-Titanium (NiTi) wires in different fluids under constant mechanical stress, Materials Science and Engineering A, 378 (2003) pp. 110-114
  O. Prymak, A. Klocke, B. Kahl-Nielke, M. Epple
  
• Hot Isostatic Pressing (HIP) of Elemental Powder Mixtures and Prealloyed Powder for NiTi Shape Memory Parts, Advanced Engineering Materials, 5 (2003) pp. 918-924
  E. Schüller, O. Hamed, M. Bram, D. Sebold, H.P. Buchkremer, D. Stöver
  
• Multiple-step martensitic transformations in Ni-rich NiTi alloys - an in-situ transmission electron microscopy investigation, Phil.Mag., 83 (2003) pp. 339-363
  A. Dlouhy, J. Khalil-Allafi, G. Eggeler
  
• Phase Fractions of B2, B19', R-Phase and Ni4Ti3 in NiTi Alloys during Two-Step Phase Transformations, J. de Physique IV, 112 (2003) pp. 811-814
  H. Sitepu, W. W. Schmahl, T. Reinecke, J. Khalil Allafi , G. Eggeler
  
• Superelastic NiTi-Alloys under Torsional Loading, J. de Physique IV, 112 (2003) pp. 807-810
  W. Predki, M. Klönne
  
• A micromechanical model for polycrystalline shape-memory alloys, Materials Sience and Engineering A, 378 (2004) pp. 503-506
  K. Hackl, M. Schmidt-Baldassari, W. Zhang
  
• Electrolytic processing of NiTi shape memory alloys, Materials Science and Engineering A, 378 (2004) pp. 191-199
  M. Pohl, C. Hessing, J. Frenzel
  
• High Quality Vacuum Induction Melting of Small Quantities of NiTi Shape Memory Alloys in Graphite Crucibles, Journal of Alloys and Compounds, 385 (2004) pp. 214-223
  J. Frenzel, Z. Zhang, K. Neuking, G. Eggeler
  
• Machining of NiTi Based Shape Memory Alloys; Materials Science and Engineering A, 378 (2004) pp. 180-184
  K. Weinert, V. Petzoldt
  
• Multiple-step martensitic transformations in Ni-rich NiTi shape memory alloys, Scripta Mater., 50 (2004) pp. 187-192
  M.C. Carroll, Ch. Somsen, G. Eggeler
  
• Recent developments in shape memory thin film technology, Mater. Sci. and Eng. A, 378 (2004) pp. 40- 46
  B. Winzek, S. Schmitz, H. Rumpf, T. Sterzl, R. Hassdorf, S. Thienhaus, J. Feydt, M. Moske, E. Quandt,
  
• Structural and functional fatigue of NiTi shape memory alloys, Mat. Sci. Eng. A, 378 (2004) pp. 24-33
  G. Eggeler, E. Hornbogen, A. Yawny, A. Heckmann, M. Wagner
  
• Structural fatigue of pseudoelastic NiTi shape memory wires, Mat. Sci. Eng. A, 378 (2004) pp. 105-109
  M. Wagner, T. Sawaguchi, G. Kausträter, D. Höffken, G. Eggeler
  
• Surface energies and size-effects in shapememory-alloys, Mat. Sci. Eng. A, 378 (2004) pp. 499-502
  K. Hackl, M.Schmidt-Baldassari, W. Zhang, G. Eggeler
  
• Metal Injection Molding for Prealloyed NiTi Shape Memory Alloys, Journal of Material Science, 40 (2005) pp. 4231-4238
  E. Schüller, L. Krone, M. Bram, H.-P. Buchkremer D. Stöver
  
• On the Reaction between NiTi Melts and Crucible Graphite during Vacuum Induction Melting of NiTi Shape Memory Alloys, Acta Mater., 53 (2005) pp. 3971-3985
  Z. Zhang, J. Frenzel, K. Neuking, G. Eggeler
  
• Improvement of mechanical properties of powder metallurgical NiTi Shape Memory Alloys, Advanced Engineering Materials,8 (2006) pp. 247-252
  J. Mentz, M. Bram, H.-P. Buchkremer, D. Stöver
  
• Vacuum Induction Melting of Ternary NiTiX (X = Cu, Fe, Hf, Zr) Shape Memory Alloys Using Graphite Crucibles, Materials Transactions JIM, 48 (2006) pp. 661-669
  Z. Zhang, J. Frenzel, K. Neuking, G. Eggeler
  
• Evaluation of NiTi as a carrier material for human mesenchymal stem cells, Langenbecks Arch. Surg., 392 (2007) pp. 813
  T. Habijan, M. Köhl, O. Bremm, S.A. Esenwein, D. Stöver, G. Muhr, M. Köller
  
• On the Influence of Carbon on Martensitic Phase Transformations in NiTi Shape Memory Alloys, Acta Mater., 55 (2007) pp. 1331-1341
  J. Frenzel, Z. Zhang, C. Somsen, K. Neuking, G. Eggeler
  
• Functional Fatigue of Shape Memory Polymers, Advanced Engineering Materials, 10 (2008) pp.922-927
  C. Schmidt, K. Neuking, G. Eggeler
  
• Lattice stability, elastic constants and macroscopic moduli of NiTi martensites from first principles, Acta Materialia, 56 (2008) pp. 6232-6245
  M. F.-X. Wagner, W. Windl
  
• Powder metallurgical processing of NiTi shape memory alloys with elevated transformation temperatures, Mat. Sci. Eng. A, 491 (2008) pp. 270-278
  J. Mentz, J. Frenzel, F.-X. Wagner, K. Neuking, G. Eggeler, H.-P. Buchkremer, D. Stöver
  
• Fracture mechanics and microstructure in NiTi shape memory alloys, Acta Materialia, 57 (2009) pp. 1015-1025
  S. Gollerthan, M. L. Young, A. Baruj, J. Frenzel, W. W. Schmahl, G. Eggeler
  
• Mesoscale kinetics produces martensitic microstructure, Journal of the Mechanics and Physics of Solids, 57 (2009) pp. 109-121
  O. Kastner, G. J. Ackland
  
• Microstructural evolution during multiaxial deformation of pseudoelastic NiTi studied by first-principles-based micromechanical modeling, Acta Materialia, 57 (2009) pp. 3856-3867
  R. Heinen, K. Hackl, W. Windl, M. F.-X. Wagner
  
• Influence of Ni on martensitic phase transformations in NiTi shape memory alloys, Acta Materialia, 58 (2010) pp. 3444-3458
  J. Frenzel, E. P. George, A. Dlouhy, C. Somsen, M. F.-X. Wagner, G. Eggeler
  

Completed projects