About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
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Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
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Presentation Title |
Characterizing Interface Diffusion Mechanisms in Al and Al-Si Alloys via Atomistic Simulations |
Author(s) |
Ian Chesser, Raj Koju, Yuri Mishin |
On-Site Speaker (Planned) |
Ian Chesser |
Abstract Scope |
Interface diffusion and interfacial slip are two key processes contributing to the high-temperature creep deformation of metal-matrix composites. Fundamental understanding of these processes remains poor. Atomistic simulations are a promising route toward understanding, but reliable methodology for measuring kinetic coefficients and disentangling competing mechanisms has not been developed. Here, we compare interface diffusion coefficients and mechanisms in pure Al grain boundaries to those in Al-Si phase boundaries for a range of interface types. Some features of interface diffusion are found to be universal, including the existence of collective diffusion mechanisms and dynamical heterogeneity. The Al-Si phase boundaries exhibit additional complexity, including possible glassy behavior and processing-history dependent ordering effects.To identify rate controlling mechanisms of interfacial creep, shear deformation simulations are conducted for selected phase boundaries over a range of strain rates. Interface diffusion and sliding mechanisms are found to be distinct, but correlated processes. |