On Shock Process And Phase Transformation Of Ti Irradiated By High-Intensity Pulsed Ion Beam

The experimental investigation of phase composition, crystalline preferred orientations and dynamic process on pure Ti irradiated by high-intensity pulsed ion beam (HIPIB) were performed in TEMP-6 HIPIB apparatus, TEMP-4M HIPIB apparatus and ETIGO-II apparatus, respectively.The stress waves induced in the irradiated pure Ti have been measured by using lead-zirconte-titanate (PZT) piezoelectric sensor with central frequency of 10 MHz during HIPIB irradiation at the ion current density of 200-400 A/cm2. With increasing the ion current density from 100 to 400 A/cm2, the magnitude of stress wave for pure Ti increased from 4 to 70 MPa. The intensity of recoil stress wave increased apparently with the increase of ion current density.Two mechanisms account for the generation of stress wave, i.e. thermoelastic and recoil, which resulted in the fomation of thermoelastic stress wave and recoil stress wave, respectivly. During initial irradiated stage, Thermoelastic stress waves are induced because of asymmetrically thermal expanding in the Ti sample. With irradiation going on, the irradiated Ti melt and innerstress releases. The melting Ti heat up sequentially, the irradiated Ti evaporates and droplet ejects. Base on law of conservation of momentum, it will induce shock stress wave.HIPIB irradiation of pure Ti was performed at an energy density of 1-100 J/cm2 with a shot number of 1-50 at 2.0×10-2 Pa base pressure. The surface of irradiated Ti melts, evaporates and ablates. The melting is primary and new phases form for the irradiated Ti at 1 J/cm2. While the energy density above 3 J/cm2, the surface Ti evaporates and ablates strongly so that no new phase forms. At lower energy density, the nitriding/carbonizing phase of Ti form at irradiated Ti surface and C/N diffuse into the Ti matrix with increasing shots. It also can be observed that the crystalline preferred orientations of Ti irradiated by HIPIB are different from original Ti.<103> crystalline preferred orientations formed after irradiating. The crystalline preferred orientations change obviously after 1 shot and change slowly with increasing shots number continually.