Study on Electrical Resistivity of NiTi Alloy by First-Principles and Boltzmann Theory

NiTi shape memory alloy has been widely used as intelligent material due to its unique shape memory effect and superelasticity. Electrical resistivity plays a critical role in transformation behavior analysis, microstructure tailoring and signal feedback in actuating. In order to develop a better understanding of the electrical resistivity of different phases (B2, B19′) of NiTi alloy, first-principles and Boltzmann theory calculations were executed. The structure properties and electronic band structures of B2 and B19′ phases in NiTi alloy were obtained, based on which the electrical resistivities were calculated. From the calculated results, the B2 phase has an absolute bandgap of 1.7095 eV and an electrical resistivity of \({1}{\text{.44}} \times {10}^{{ - 7}} {\Omega m}\) , while the B19′ phase has an absolute bandgap of 0.5769 eV and an electrical resistivity of \({8}{\text{.86}} \times {10}^{{ - 7}} {\Omega m}\) . Furthermore, the electrical resistivity of B2 phase under elastic strain was investigated. The calculated results show that the resistivities of different phase is related to the band gap. This work has made a beneficial exploration on electrical resistivity calculations of the basic phase in NiTi alloy, which lays the foundation for the further study of transformation behaviors and electrical behaviors of NiTi alloy.