MOSSBAUER STUDY OF MARTENSITIC-TRANSFORMATION IN XE ION-IRRADIATED TYPE-304 AUSTENITIC STAINLESS-STEEL

Foil specimens of type 304 stainless steel have been irradiated with Xe+ ions in the range of 100-400 keV and 1 x 10(20)-1 x 10(21) ions/m2 to elucidate the dynamics of the ion-induced martensitic phase transformation in stainless steel. It has been clearly shown by depth selective conversion electron Mossbauer spectroscopy (DCEMS) that the ion-induced martensitic phase in type 304 stainless steel has grown from the surface to a depth dependent both on the ion energy and the fluence of the Xe+ ions. Especially, we observed by means of DCEMS that the extension of the martensitic phase into the interior of stainless steel has been induced with increasing ion energy. It is concluded from these results that the depth distribution of the ion-induced martensitic phase is stress-induced by the formation of the highly pressurized Xe+ inclusion in type 304 stainless steel.