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The thermal evolution of defects introduced in silicon by line scanning with helium ion microscopy was investigated, confirming that the evolution of the defective structure after annealing at 650 °C for 1 h results in a central void channel and a sector ring of cavities surrounding it, located in the amorphous and transition regions of the unannealed pre-irradiated sample, respectively. The variation of defective structures with annealing temperature and ion dose indicates that high temperature is favorable for the formation of void channels and cavities, and the coarsening and recrystallization processes compete in the shaping of a void channel. The total volume of the defective structure is linearly related to the ion dose, while the zoning phenomenon is attributed to the differences in the vacancy amounts within their locations. These results provide direct experimental evidence for the thermal evolution of defects with zonal characteristics induced by precisely localized helium irradiation. • An experimental study of the evolution of defects induced by precisely localized irradiation of He + FIB was conducted. • A nanostructure characterized as a single central void channel surrounded by a sector ring of cavities was deposited. • The zonal evolution of defects is reasonably explained based on the distribution of helium and vacancies implantation. [ABSTRACT FROM AUTHOR]

Photochromic materials have received increasing interest benefited by its promising application in anti-counterfeiting and erasable optical information storage with the rapid development of the information age. In this work, we have reported a perovskite configuration SrHfO 3 :Eu3+ photochromic powders, displaying the color changed from white to brown upon UV light irradiation, and it can be bleached by 365 nm light or heat treatment. Based on the energy transfer, the Eu3+ ions doped into SrHfO 3 host to obtain luminescence modulation attribute to the special excitation (302 and 396 nm) and emission (614 nm) properties, and the more efficient luminescence modulation is excited at 396 nm. The storage of verbal, images and digital signal can be realized by UV light irradiation, then the stored information can be read out through 254 nm light, and the recording information can be erased using 365 nm light illumination. In addition, the anti-counterfeiting application has achieved by employing alternating UV and 365 nm light illumination. Furthermore, the stored information undergoes several cycles with almost no degradation of "written in", "read out" and "erased", displaying excellent fatigue resistance and reversibility. These results suggest that the perovskite configuration SrHfO 3 :Eu3+ photochromic material has promising multi-functional application in optical information storage and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

• A multiscale model describing the evolution of helium bubbles is established based on the rate equations and the population balance equation. • The model can effectively describe the nucleation and evolution of helium bubbles. • The model contains bubble evolution mechanisms including "migration and coalescence (MC)" and "Ostwald ripening (OR)". • The model allows for independent statistics on the contribution of MC and OR, as well as an explanation of their coupling effects. A multiscale model describing the evolution of helium bubbles in the irradiated materials is established based on the rate equations and the population balance equation. The size distribution of the helium bubbles and the evolution law of the statistical average size and number density of the bubbles with time changing predicted by the model are in good agreement with the experimental statistics. The influence of annealing temperature, annealing time, irradiation energy, irradiation flux, and coarsening mechanisms on the evolution of helium bubbles are numerically simulated and discussed, taking FeCrAl alloy as the irradiated material. The results show that the bubble evolution is dominated by the Ostwald ripening mechanism under high temperature annealing conditions (≥ 1073 K), and the time dependence of the average size and density of helium bubbles is consistent with the existing theoretical results. And the number of shrinking helium bubbles caused by Ostwald ripening is effectively reduced by the bubble coalescence effect, leading to further growth of the proportion of large-sized helium bubbles. Consequently, a Gaussian bubble size distribution has been obtained modeling the coupling of the Ostwald ripening mechanism and the bubble coalescence mechanism. The generation rates of helium and vacancy in the material during irradiation, as well as their ratio, are significant factors that can affect the nucleation and evolution of helium bubbles. [ABSTRACT FROM AUTHOR]

• Helium ion-irradiation responses in Mo-Re alloys at room temperature were evaluated via micro-pillar compression. • Orientation-dependent irradiation-induced hardening is obvious in low Re Mo-Re alloys, while is weak on high Re alloys. • Irradiated pillars with [1 0 0] orientation all shows higher flow stresses than pillars with [1 1 0] orientation after yield. Helium ion-irradiation responses in molybdenum (Mo) and molybdenum-rhenium (Mo-Re) alloys at room temperature were evaluated via micro-pillar compression. Irradiation-induced hardening is closely dependent on orientation in Mo-Re alloys with low Re content, while is weak orientation-dependence on high Re alloys. Irradiated pillars with [1 0 0] orientation all shows higher flow stresses than pillars with [1 1 0] orientation after yield, which is distinguishing from pillars before irradiation that has been shown in our previous work. High density of dislocation loops and helium bubbles after irradiation at room temperature induces severe hardening in Mo. Voids / small loops induced by irradiation lead to less hardening in Mo-Re alloy than in Mo. No precipitation is observed in all samples, which may be attributed to low irradiated temperature and implantation energy. [ABSTRACT FROM AUTHOR]