| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Mechanical Response of Materials Investigated Through Novel In-Situ Experiments and Modeling
|
| Presentation Title |
The Role of Precipitates on Cyclic Stability of NiTi and NiTiCu Shape Memory Alloy Thin Films |
| Author(s) |
Hyemin Ryu, Zhuo Feng Lee, Ji-Young Kim, Sunkun Choi, Gi-Dong Sim |
| On-Site Speaker (Planned) |
Hyemin Ryu |
| Abstract Scope |
Shape memory alloy (SMA) thin films, known for their superelasticity and shape memory effect, have attracted significant attention due to their potential applications in microelectromechanical systems (MEMS). This study investigates the influence of precipitates on the cyclic behavior of submicron-thick NiTi and NiTiCu thin films through tensile and fatigue testing. X-ray diffraction confirmed austenitic phases at room temperature in both materials. NiTi has exhibited superior low-cycle cyclic stability, attributed to the uniform distribution of Ni4Ti3 precipitates. Conversely, NiTiCu showed better high-cycle fatigue stability, linked to reduced hysteresis and the presence of incoherent (Ni,Cu)2Ti precipitates at grain boundaries. These findings highlight that Ni4Ti3 precipitates in NiTi improve cyclic stability by impeding dislocation movement, while (Ni,Cu)2Ti precipitates in NiTiCu introduce strain incompatibilities, affecting fatigue stability. Understanding microstructural impacts is crucial for enhancing the reliability of SMA thin films in various applications. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Mechanical Properties, Thin Films and Interfaces, Phase Transformations |