Grain boundary chemistry

Recent advances in experimental measurements of grain-boundary segregation are reviewed. It is now feasible to measure segregation and relate it to boundary structure at the atomic level. It is also possible to measure nanometre-level segregation at dozens of grain boundaries, so a better statistical picture of the distribution of segregant is available. There is strong experimental evidence emerging for an electronic explanation of the role of segregation in controlling bulk mechanical properties, such as temper embrittlement.