The variation of electrical resistance of near stoichiometric NiTi during thermo-mechanic procedures

The variation of electrical resistance of near stoichiometric NiTi during some thermo-mechanic procedures was studied in this paper. The results show that when the R-phase does not exist in the near stoichiometric NiTi wire, the electrical resistance of NiTi wire increases linearly with the increase of strain at constant temperature. When a phase transformation or martensite reorientation takes place, the slopes of the electrical against strain curves are changed. During the cycles of tensile loading and unloading, electrical resistance of NiTi wire increases as the increase of the cycle numbers, but will stabilize after approximately 15 cycles. Furthermore, the possibility to use NiTi wire as a sensor in the intelligent materials system is discussed.