Eurekalert July 17, 2018
It is known that sulfur embrittlement is related to the grain boundary segregation of sulfur, but the underlying atomic mechanisms have remained elusive. Researchers at UC San Diego examined the general grain boundaries in nickel polycrystals doped with sulfur. They found that competition between interfacial ordering and disordering leads to the alternating formation of amorphous-like and bilayer-like facets at general grain boundaries. They also found that bipolar interfacial structures cause brittle intergranular fractures between polar sulfur-nickel structures that are disorderly aligned in two opposite directions. The discovery enriches fundamental understanding of general grain boundaries that often control the mechanical and physical properties of polycrystalline materials… read more. Open Access TECHNICAL ARTICLE
This is a faceted grain boundary in intergranularly-fractured sulfur-doped nickel. Credit: Jian Luo et al.