Site competition of impurities and grain boundary stability in iron and tungsten

Journal Article · Tue Jun 15 00:00:00 EDT 1993 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(93)90589-K· OSTI ID:6544626

Krasko, G L ^[1]

---

1. Army Research Lab., Watertown, MA (United States)

Fe-base alloys and W are among the most important ultra-high-strength materials. The purpose of this paper is to elucidate the energetics of impurities in Fe and W GBs, and analyze the effect of impurities on the intergranular cohesion at the electron-atom level. A deeper understanding of the cohesion-decohesion processes on the microscopic level will lay a foundation for a 'smart design' of more ductile and tough alloys. In particular, the theoretical analysis of the electron structure and the energetics of Fe and W GBs, both clean (CL) and with impurities, enables one to make important predictions. The calculations have shown that impurities, such as N, O, P, S, Si weaken the intergranular cohesion resulting in 'loosening' of the GBs in Fe and W. The presence of B on the contrary, enhances the interatomic interaction across the GB. The so-called 'site-competition effect' should play an important role affecting impurity distribution in GBs. Among the impurities analyzed, both in Fe and W, B in the GB has the lowest energy, and thus would tend to push other impurity atoms off the GB, thus improving resistance to brittle fracture.

• OSTI ID: 6544626
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 28:12; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON
GRAIN BOUNDARIES
MECHANICAL PROPERTIES
TUNGSTEN
BORON
DATA
DUCTILITY
EMBRITTLEMENT
FRACTURE PROPERTIES
IMPURITIES
NITROGEN
OXYGEN
PHOSPHORUS
SILICON
STABILITY
SULFUR
CRYSTAL STRUCTURE
ELEMENTS
INFORMATION
METALS
MICROSTRUCTURE
NONMETALS
SEMIMETALS
TENSILE PROPERTIES
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies
360103 - Metals & Alloys- Mechanical Properties