In Situ TEM Annealing of Ion-Amorphized Hi Nicalon S and Tyranno SA3 SiC Fibers

In this work, recrystallization of ion-amorphized Hi Nicalon Type S and Tyranno SA3 SiC fibers (4MeV Au3+, 2×1015cm−2) has been studied via in situ TEM annealing. Both fibers show a two-step recovery process of the radiation damage. First recovery stage starts at temperatures as low as 250°C and implies recovery of the radiation swelling. Eventually the amorphous layer recrystallizes with no signs of polytype change (3C-SiC). Recrystallization temperatures yield 900–920°C and 930°C for the HNS and the TSA3 respectively. HNS fiber shows columnar recrystallization perpendicular to the amorphous–crystalline interphase with a grain growth rate of ∼20nmmin−1. On the other hand, recrystallization of TSA3 fiber is rather “spontaneous” with no preferential growth direction. The different recrystallization is attributed to the different microstructure of the fibers.