The Role of Chemical Bonding in Grain Boundary Embrittlement
Abstract
Brittle intergranular fracture occurs when impurity elements segregate to the grain boundaries of a material and lower their cohesive strength. Although many embrittling elements have been identified by experimental studies, the reason why these elements cause embrittlement has remained elusive. This paper presents results of fully quantum mechanical cluster calculations which address this question. It will be shown that strong embrittling elements draw charge from the neighboring metal atoms onto themselves. They thus remove charge from the metal-metal bonds which hold the grain boundary together and weaken them. Cohesive enhancers do not draw charge off the metal atoms and thus do not weaken the metal-metal bond network. In addition, they form rather homopolar bonds with the metal atoms and thus provide an added increment of bonding in the grain boundary.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 10, 1982
- Accession Number
- ADA111399
Entities
People
- C. L. Briant
- R. P. Messmer
Organizations
- University of Pennsylvania