Identification of Quaternary Shape Memory Alloys with Near‐Zero Thermal Hysteresis and Unprecedented Functional Stability |
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| Authors: | Robert Zarnetta Ryota Takahashi Marcus L Young Alan Savan Yasubumi Furuya Sigurd Thienhaus Burkhard Maaß Mustafa Rahim Jan Frenzel Hayo Brunken Yong S Chu Vijay Srivastava Richard D James Ichiro Takeuchi Gunther Eggeler Alfred Ludwig |
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| Affiliation: | 1. Institute for Materials Ruhr‐Universit?t Bochum 44780 Bochum (Germany);2. Research Department Integrity of Small‐Scale Systems/High‐Temperature Materials (IS3/HTM) Ruhr‐Universit?t Bochum 44780 Bochum (Germany);3. Department of Materials Science and Engineering University of Maryland College Park, Maryland 20742 (USA);4. Present address: Institute of Solid State Physics, University of Tokyo, 5‐1‐5 Kashiwanoha, Kashiwa, 277‐8581 (Japan);5. Department of Intelligent Machines and Systems Engineering Hirosaki University Hirosaki 036‐8561 (Japan);6. Advanced Photon Source Argonne National Laboratory Argonne, IL 90439 (USA);7. Present address: National Synchrotron Light Source II, Brookhaven National Laboratory, Upton NY, 11973 (USA);8. Department of Aerospace Engineering and Mechanics University of Minnesota Minneapolis, Minnesota 55455 (USA) |
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| Abstract: | Improving the functional stability of shape memory alloys (SMAs), which undergo a reversible martensitic transformation, is critical for their applications and remains a central research theme driving advances in shape memory technology. By using a thin‐film composition‐spread technique and high‐throughput characterization methods, the lattice parameters of quaternary Ti–Ni–Cu–Pd SMAs and the thermal hysteresis are tailored. Novel alloys with near‐zero thermal hysteresis, as predicted by the geometric non‐linear theory of martensite, are identified. The thin‐film results are successfully transferred to bulk materials and near‐zero thermal hysteresis is observed for the phase transformation in bulk alloys using the temperature‐dependent alternating current potential drop method. A universal behavior of hysteresis versus the middle eigenvalue of the transformation stretch matrix is observed for different alloy systems. Furthermore, significantly improved functional stability, investigated by thermal cycling using differential scanning calorimetry, is found for the quaternary bulk alloy Ti50.2Ni34.4Cu12.3Pd3.1. |
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| Keywords: | actuators alloys medical applications shape‐memory materials thin films |
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