Grain boundary segregation irradiation effects

The effect of P on irradiation embrittlement was also attributed to segregation leading to temper embrittlement. However, there is direct physical evidence of radiation-induced P segregation at grain boundaries. 

As described in Section 2.1.2, irradiation can therefore alter dramatically the level of segregants at grain boundaries. The mechanism responsible is the inverse Kirkendall effect, and in a nickel-base alloy such as PEI6 the boundaries could be depleted in chromium and iron and enriched in nickel 1.16.17]. Once the effect of radiation had been removed by annealing at 871 K for I h the alloy was able to return to its original. state. 

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