Thermodynamics of martensite transformation hysteresis in
Ni-Ti shape memory alloys①
Ni-Ti shape memory alloys①
(1. College of Materials Science and Engineering,
Tianjin University, Tianjin 300072, P.R.China;
2. Department ofFundamental Subjects,
Tianjin Institute of Urban Construction, Tianjin 300381, P.R.China)
Tianjin University, Tianjin 300072, P.R.China;
2. Department ofFundamental Subjects,
Tianjin Institute of Urban Construction, Tianjin 300381, P.R.China)
Abstract: A thermodynamic calculation method on the temperature hysteresis of thermoelastic martensite transformation in Ni-Ti shape memory alloys was developed. The thermodynamic analysis indicates that the irreversible consumed energy and the elastic energy are the important factors influencing transformation hysteresis. It is revealed that the wide inherent transformation hysteresis can be attributed to the higher irreversible consumed energy of martensite transformation in Ni-Ti-Nb based alloys than those of Ni-Ti binary alloys.
Key words: thermodynamics; thermoelastic martensite; temperature hysteresis; Ni-Ti alloys