Mechanical response of NiFeGa alloys containing second-phase particles

Tensile and compressive strain-temperature and stress-strain responses have been used for the first time to investigate the effects of second-phase particles on the deformation of NiFeGa shape memory alloys. Particles are conducive to the dissipation of stored energy; stress and thermal hysteresis increase three-fold in aged alloys. Although dissipation is severe, recoverable strain levels are as large as +12% and -6%, which match strains for the unaged alloys. These results demonstrate that second-phase particles can be used to tailor the hysteresis while maintaining large transformation strains.