Ronald Gibala

Professor Emeritus

2028 HH Dow
T: (734) 936-0178




First Principles Calculations of Defect Interactions in Metallic Materials

Collaborators: Collaborators: W. A. Counts (QuesTek Innovations LLC), C. Wolverton (Northwestern University)
Sponsor: General Motors Corporation
This program addresses the problem of understanding the structure of atomic-level imperfections (e.g., point defects, dislocations, grain boundaries) in metals, how they interact and how the interactions affect mechanical properties. A major topic involves the interaction of hydrogen as an interstitial solute with: other hydrogen atoms; other solutes, both interstitial and substitutional; vacancies; screw dislocations; and simple tilt boundaries. Using first principles density functional theory, we calculate the binding energies of hydrogen to each of the imperfections and assess their potential role in causing or affecting hydrogen embrittlement, especially in iron-base materials. The analysis of this topic and others includes detailed examination of related experimental research. A schematic illustration that depicts some of the results on hydrogen in body-centered cubic iron, which are in good agreement with available experiments, is given in the enclosed figure.