Electron irradiation-induced changes of martensitic transformation characteristics in a TiNiCu shape memory alloy

A narrow hysteresis TiNiCu shape memory alloy was irradiated by 1.7 MeV electrons by electron electrostatic accelerator. The irradiation temperature was below the martensite finish temperature. The transformation temperatures and the latent heat of phase transformation were measured by a differential scanning calorimeter (DSC). The results indicated that the transition temperatures were raised and the hysteresis was increased by the irradiation. Thus, the martensite was. stabilized by the irradiation. While the enthalpy and entropy differences of the martensitic and parent phases were reduced slightly, the driving force of martensite nucleation was raised for 40% and the stored elastic energy of martensite decreased for 30% after the irradiation by electrons to a dose of 11.1 x 10(20) m(-2). Their changes were rather substantial for the electron irradiation-induced stabilization of martensites from a thermodynamical analysis. (C) 2002 Elsevier Science B.V All rights reserved.