In-situ He+ irradiation induced crystallization on crystalline/amorphous ZrC films

The irradiation behaviors of crystalline/amorphous ZrC films, prepared by magnetron sputtering, were investigated by the method of 30 keV He+ irradiation combined with an in-situ TEM observation at 573 K. The results indicate that the amorphous-nanocrystalline transformation occurred in amorphous layer, which is mainly attributed to He+ irradiation compared with the phenomenon of in-situ annealing at 593 K. Meanwhile, the nanocrystals in amorphous layer, nucleating and growing near the amorphous/crystalline interface firstly, are independent from pristine crystals in the inner layer. The thermal spike model is suggested to explain the evolution of crystallization. During He+ irradiation, the diffusion of Zr and C interstitials is enhanced by the deposited energy from the electronic energy loss, which contributes to the crystallization of ZrC as the C to Zr elements ratio decreases in the amorphous layer.