Fundamental Concepts Relating Local Atomic Arrangements, Deformation, and Fracture of Intermetallic Alloys
Abstract
This final contract report describes research activities on two topics of fundamental importance for application of intermetallic alloys as elevated temperature engineering materials: brittle fracture and creep resistance. On the topic of brittle fracture, the process of crack tip plasticity has been investigated by extending the Rice-Thomson model to treat the case of crack tip emission of dissociated superlattice dislocations that commonly occur in intermetallic alloys The model shows that superlattice dislocation emission from crack tips can be inhibited in intermetallic alloys, and predicts the occurrence of cleavage fracture in particular intermetallic alloys. The fracture mode predictions can be compared with experimentally observed fracture modes; such comparisons for intermetallic alloys with the L12 and B2 crystal structures show that the model predictions match the experimental observations for every intermetallic alloy where sufficient data are available to perform the model calculations (about 25 alloys in all). A novel result of the dislocation emission modeling work is the finding that the antiphase boundary energy plays a central role in determining whether a particular intermetallic alloy will exhibit cleavage fracture or not.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1993
- Accession Number
- ADA268745
Entities
People
- J. A. Wert
Organizations
- University of Virginia