Shape Setting of High Performance Beta Titanium SMA
J.E. Schaffer, Ph.D., Senior Research and Development Engineer & S. Cai, PhD, Research and Development Engineer
In our July 2015 installment , we discussed Fort Wayne Metals’ recent development of a beta titanium, nickel-free superelastic alloy. At the time, as shown in Figure 1 below, we were able to design excellent shape setting response in linear wire segments, e.g. for applications such as kink-resistant guidewire and stylets. Straight shapeset geometries were achieved through conventional stress-annealing of a suspended wire segment as well as continuous reel-to-reel wire lengths. On the contrary, complex, e.g. Nitinol-like, wire forms require contact-fixtures as well as alternative heating modes and atmospheres that increase performance-specific design complexity. More recent developments, highlighted briefly in Figure 2, include specific processing techniques to shape set the same Ni-free alloy (code named RD149-16) into functional forms with varied mechanical behavior. Such forms can be designed and engineered in a “nitinol-like manner” to serve as dental files, orthodontic arch wires, textiles for stents, aneurysm-filling scaffolds, and other medical device forms where Nitinol is currently used.
Figure 1 – Elastic property tuning by shape-setting a single composition of beta Ti alloys at various temperature and time, from .
Figure 2 – Shape set processing results in Ni-free titanium beta alloy “RD149-16” showing (a) low plateau stress “low force” tuning; (b) high plateau stress “high force” tuning; and (c) a simple multi radius shape set form using 0.40 mm (0.016 in) wire with small and large bend radii of 0.50 and 3 mm respectively.
We welcome your next challenge! Fort Wayne Metals is your partner in not only alloy design, but also function-specific processing and product development. Our strength lies in many years’ hands-on experiences as well as our fundamental knowledge of material science and mechanical engineering [2-5]. Call (+1.260.747.4154), email [email protected], or text (+1.260.438.4119) us, the Fort Wayne Metals R&D Team, with your product idea and challenge us to develop a satisfying solution.
 Bi-monthly Update: July 2015
 S. Cai, J.E. Schaffer, Y. Ren, “Deformation of a Ti-Nb alloy containing α"-martensite and omega phases”, Applied Physics Letters 106, 131907 (2015); doi: 10.1063/1.4916960
 S. Cai, J.E. Schaffer, C.Yu, M.R. Daymond, Y. Ren, "Evolution of Intergranular Stresses in a Martensitic and an Austenitic NiTi Wire During Loading–Unloading Tensile Deformation", Metallurgical and Materials Transactions A 2015, DOI 10.1007/s11661-015-2845-0
 S. Cai, J.E. Schaffer, Y. Ren and M.R. Daymond, “Discovery of a <210> fiber texture in medical-grade metastable beta titanium wire”, Acta Materialia 87 (2015) 390–398
 S. Cai, M.R. Daymond, Y. Ren, J.E. Schaffer, "Evolution of lattice strain and phase transformation in Beta III Ti alloy during room temperature cyclic loading", Acta Materialia, 61 (2013) 6830-6842
Disclaimer: Our monthly highlights are sneak peeks of what our R & D department is working on. This does not mean we have what is referenced above ready for manufacturing.
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