Irradiation Induces Phase Transformation And Change Of Transformation Characteristics On The Alloys

Ion beam irradiation can affect the martensitic transformation and induce the amorphous transition by production, accumulation of defects and atomic disordering in alloys. The irradiation-induced dislocation loops and amorphous transition strongly affect the properties of materials. The TiNi-base shape memory alloys (SMAs) and Zircaloys are chosen to study irradiation-induced diffusion-dependent and diffusion-independent phase transformation, irradiation-induced dislocation loops. And the effect of irradiation on the martensitic transformation characteristics is also studied. To the authors' knowledge, these research results in this dissertation have not been reported. ?350KeV electron irradiation can induce the martensitic transformation in the TM SMAs, and 300KeV electron irradiation can't. The critical displacement energy of the TiNi SMAs is between 16 and 19eV calculated by this result. (2) 4000KV Transmission Electron Microscope may be used to study in-situ irradiation effect of the TiNi SMAs. (3) The process of heavy ions-induced the amorphous transition are observed at HVEM-Tandem facility at Argonne National Laboratory. The disordering and amorphization of the TiNiCu SMAs is induced with 400KeV Xe ion irradiation at a dose of 0.05dpa and 0.4dpa at room temperature, respectively. The disordering and amorphization of a Zr(Cr,Fe)2 precipitate in Zircaloy 4 is produced with 600KeV Ne ion irradiation at a dose of 0.4dpa and 2.7dpa at 350 癈, respectively. Recrystallization of this precipitate is also induced when irradiation to 7dpa. The critical amorphization dose and temperature are obtained according to this result. ?The electron irradiation with small doses shifts the martensitic transformation temperatures in the TiNi-base SMAs. The As is increased in the TiNiCu SMAs, but the irradiation has no detectable effect on Ms. However, Ms in the TiNi SMAs is strongly decreased, and the irradiation has little effect on the other transformation temperatures. ?The high density dislocation loops are produced by 2MeV proton irradiation. The loop density and dimension increase with increasing proton dose. The micro-hardness also increases with the dose and becomes saturated at a dose of Sdpa.