Hydrostatic pressure-induced transition in grain boundary segregation tendency in nanocrystalline metals

Impurity segregation at grain boundaries (GBs) can have a profound impact on the mechanical behavior of nanocrystalline metals. In this study, we employ atomistic simulations to investigate the effects of hydrostatic pressure on the GB segregation energy spectra in a series of binary alloy systems. Our results demonstrate that, depending on the alloy system, hydrostatic pressure can either enhance or hinder GB segregation tendencies. However, in specific alloys, such as AlMg and NiNb, hydrostatic pressure can also result in transitions in the preferred segregation sites, characterized by an initial increase followed by a decrease at certain pressures. The underlying mechanisms for these transitions can be attributed to the changes in the elastic component brought about by hydrostatic pressure, which dominate the other contributions to the total segregation energy.