Akademik Veri Yönetim Sistemi
The 6th International Conference of Materials and Engineering Technology (TICMET'25), Gaziantep, Türkiye, 6 - 08 Ekim 2025, ss.0-1, (Tam Metin Bildiri)
Shape memory alloys (SMAs), particularly NiTi-based systems, exhibit unique functional properties such as the shape memory effect and superelasticity due to reversible phase transformations. However, their application is limited by functional fatigue and degradation under cyclic loading, especially in doped and high-entropy variants. This study investigates the effects of Fe and Co additions on the mechanical behavior of NiTi alloys using molecular dynamics (MD) simulations. A series of uniaxial tensile tests was performed on nanostructured NiTi systems with 2–8 at. % substitution of Ni by Fe or Co using the LAMMPS simulation package and a MEAM potential. Simulations were conducted at 1 K with high strain rates to observe stress – engineering strain behavior and quantify changes in elastic modulus, ultimate tensile strength (UTS), and engineering strain at failure. The results showed that Fe doping led to a reduction in UTS and ductility with minimal change in stiffness, suggesting degradation in phase stability and transformation capacity. In contrast, Co additions increased the elastic modulus significantly, indicating enhanced lattice stiffness, but also caused moderate reductions in both UTS and ductility. These findings are consistent with literature reports linking Fe to the formation of brittle secondary phases and Co to stabilization of the austenite structure. The study confirms a trade-off between strength, stiffness, and ductility when doping NiTi with transition metals, emphasizing the importance of composition control in alloy design. While limitations exist due to simulation scale and strain rates, this study provides atomistic insights into dopant effects and offers a foundation for future multiscale studies aimed at optimizing the performance of NiTi-based shape memory alloys (SMAs) in advanced applications.