Scientific Understanding of Interfaces
Abstract
Scientific studies of material interfaces (phase boundaries, grain boundaries and precipitation) areparamount to understanding the material performance and crucial to safety and durability analyses of new aerospace structures. Despite the need to understand interfaces, most analyses and experiments in materials sciences and engineering have focused on bulk properties and homogenous idealizations bypassing the presence of interfaces. Such an idealized treatment is unable to capture the local stresses leading to irreversibilities and localizations, hence does not lend itself to further development of new materials with unusual transformations, boundaries and strengthening phases. In this study, the aim is to substantially modify our treatment of materials with full consideration of interfaces. In such a way, the interface character becomes a signature of the material akin to grain size, crystallographic texture and yield stress. To achieve such an objective, we develop a theory for rapid assessment encompassing material anisotropy, crystal lattice types, defect structures and local strain fields. With such a formalism, the resultant dislocation and disconnection networks that minimize the strain energy will be established along with the internal stress fields. These internal stress fields at interfaces are of critical importance for the flow CRSS (Critical Resolved Shear Stress) prediction. Therefore, for a given material, the proposal will map out the key parameters including the CRSS at interfaces. The theory will be exercised on a number of metals and alloys, and the experiments at nano-scale will verify the predicted misfit-induced defect networks and local strains. As a whole, our plan is to generate new knowledge in understanding of internal interfaces that is recognized as a vital sub-field of materials science and engineering.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 30, 2018
- Source ID
- FA95501810198
Entities
People
- Huseyin Sehitoglu
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign