About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling
|
Presentation Title |
Mechanical and Actuation Fatigue in Ni-Rich NiTiHf High Temperature Shape Memory Alloys |
Author(s) |
Behrouz Haghgouyan, Benjamin Young, Ibrahim Karaman, Dimitris C Lagoudas |
On-Site Speaker (Planned) |
Behrouz Haghgouyan |
Abstract Scope |
Shape Memory Alloys (SMAs) are a unique class of metals that undergo shape change as a function of temperature. SMAs, like NiTi, can be used as solid-state actuators that can be up to 1/10 the size and weight of conventional ones. The inherently low transformation temperatures of NiTi SMAs has led to development of high-temperature SMAs (HTSMAs). There is very limited knowledge on the fatigue and fracture behavior of HTSMAs, which is of great importance for their successful integration into applications. In this work, crack growth behavior in a Ni-rich NiTiHf HTSMA is investigated under two thermo-mechanical loading paths: isothermal, i.e. mechanical loading under constant temperature; and actuation, i.e. thermal cycling under constant load. The results indicate relatively brittle fracture behavior compared to that of NiTi SMAs. This can be explained by limited presence of dissipation mechanisms such as phase transformation, shown by digital image correlation, near the crack tip. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |