SEDL / STP / STP782-EB / STP34394S

Effect of Radiation-Induced Segregation on Void Nucleation

Si-Almed, A
Research scientist, Centre des Sciences et de la Technologies Nucleaires, Algiers,

Wolfer, WG
Professor, University of Wisconsin, Madison, WI

Pages: 15    Published: Jan 1982

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Abstract

The effect of segregation on void nucleation is investigated utilizing previous results for the capture efficiency of coated void. First, it is shown that any segregation, whether or not it leads to actual precipitation, leads to a modification of the bias factors for any sink. Small increases of either the lattice parameters or the elastic moduli result in reduced interstitial bias factors. Second, segregations to void embryos not only changes their capture efficiencies but also the surface energy. The effect of these changes on the void nucleation rate is studied in quantitative terms. When the segregation to voids results in an increase of the local lattice parameter by 0.4% or an increase of the shear modulus by 3%, the ultimate void nucleation rate is reached. Further increases no longer enhance void nucleation. Void nucleation without segregation effects would only be possible if the dislocation bias exceeds 50%. With segregation, void nucleation is not strongly dependent on the dislocation bias.