ELECTRON RADIATION INDUCED VOID SWELLING AND GRAIN BOUNDARY SEGREGATION IN AN Fe-Cr-Mn AUSTENITIC ALLOY

The behavior of void swelling and segregation in Fe-15Cr-xMn alloys and an alloy con- taining small amount of W and V was investigated by electron-irradiation.The compositional analysis in the irradiated regions including grain boundaries was performed.The resultdts show that there are many common features of irradiuation tehavior in the Fe-Cr-Mn and Fe-Cr-Ni systems while there are some significant differences,In the Fe-Cr-Mn alloy sys- tems void swelling was rematrkably suppressed and at the same time the radiation-induced segregation was also retarded,furthermore,the segregation was strongly retarded in an Fe-15Cr-15Mn alloy containing small amount of W and V.The results also show that Ni re- placed by Mn does not in general confer immunity from either swelling or phase instabilities. The phase instability is due to the different diffusion behavior of Ni and Mn in reponse to the operation of the inverse-Kirkendall effecr.Fe segregates to the microstructural sinks in the Fe-Cr-Mn alloys.The segregation of Fe often leads to the formation of ferrite.This fact is beneficial to reducing the swelling rate and segregation on the grain boundaries.