EFFECT OF 690-KEV XE ION IRRADIATION ON THE MICROSTRUCTURE OF AMORPHOUS MOSI2 SIC NANOLAYER COMPOSITES/

The effect of 690-keV Xe ion irradiation at three different dosage lev els, 1 x 10(15), 5 x 10(15) and 10 x 10(15)/cm(2), on the microstructu re of amorphous-MoSi2/amorphous-SiC nanolayer composites has been stud ied using transmission electron microscopy. Results show that the dept h of radiation damage in this multilayer material is similar to 80 nm, which agrees qualitatively well with the calculated damage depth calc ulated by TRIM [1]. A diffraction ring corresponding to the (10 (1) ov er bar 1) plane of C40 MoSi2 was found in the electron diffraction pat tern taken from the irradiated regions; the C30 phase is also found af ter thermal annealing of amorphous MoSi2 at 500 degrees C or above. In the damaged regions SiC layers were found to spheroidize while the na nocrystalline grains in the MoSi2 layers appeared to coarsen with incr easing dose.