Ti-50.6at.%Ni shape memory alloy specimens were irradiated in the parent phase using a tandem accelerator by 18 MeV protons at a dose rate of 4.27

TiNiCu shape memory alloy samples were irradiated by 400 keV Xe+ ions at room temperature. The in situ TEM observation showed that samples were amorphized at ～0.4dpa and the recrystallization after amorphization started when annealing at 550K and basically finished at 1023K.

A two-way shape memory effect (TWSME) spring that could elongate upon heating and contract upon cooling was obtained by constrained annealing and thermo-mechanical training. The effect of heat treatment and thermomechanical training on the TWSME and the effect of training on the transformation temperatures had been studied by elongation-temperature, electrical resistance measurements and differential scanning calorimetry (DSC). The TWSME recovery rate of extension spring increases with increasing the training cycles and increases to a saturation value. The inverse martensitic and martensitic temperatures decreased with increasing thermo-mechanical training cycles.

The isometric pyrochlore structure, A2B2O7, is generally susceptible to radiation damage, but certain compositions are remarkably resistant to radiation damage. In the binary system Gd2(Ti22xZrx)O7, the radiation resistance increases dramatically with the substitution of Zr for Ti, until the pure end member Gd2Zr2O7 cannot be amorphized, even at doses as high as; 100 dpa. Although zirconate pyrochlores are generally considered to be radiation resistant, we report results for the amorphization of a zirconate pyrochlore La2Zr2O7 by ion beam irradiation; 5.5 dpa at room temperature!. The critical amorphization temperature Tc is low,; 310K. The susceptibility to ion-beam-induced amorphization and structural disordering for zirconate pyrochlores is related to the structural deviation from the ideal fluorite structure, as reflected by the x parameter of the O48f.

The effect of irradiation on the martensitic transformation of TiNi shape memory alloys was studied by transmission electron microscopy (TEM) with in situ observation and differential scanning calorimeter (DSC). The results of TEM and DSC measurements show that the microstructure of samples is R phase at room temperature. Electron irradiations were carried out using several different TEM with accelerating voltages of 200, 300, 400 and 1000kV. Also the accelerating voltage in the same TEM was changed to investigate the critical voltage for the effect of irradiation on phase transformation. It was found that a phase transformation occurred under electron irradiation above 350kV, but never appeared at 340kV or lower accelerating voltage. Such phase transformation took place in a few seconds of irradiation and was independent of atom diffusion. The mechanism of electron-irradiation-induced the martensitic transformation is due to displacements of atoms from their lattice sites produced by the acceleratedelectrons. The critical displacement energy of TiNi SMAs is B18 eV from the results.