About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
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Symposium
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Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
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Presentation Title |
Vacancies and Other Grain-boundary Surfactants and Their Effect on Grain Growth |
Author(s) |
W Craig Carter, Arun Baskaran, Daniel Lewis, Catherine Bishop |
On-Site Speaker (Planned) |
W Craig Carter |
Abstract Scope |
A grain boundary's excess quantities (e.g., entropy, volume, and chemical species content) are determined by system's equilibrium phase(s). Even if a--possibly multiphase--polycrystal is closed with respect to exchange of chemical species (i.e., fixed composition), the grain boundary is an open system with respect to the equilibrium phases whether they abut the grain boundary or not. Thus--in the artificial case where the total grain boundary area can be treated as fixed--the excess grain boundary concentrations and the bulk compositions depend on the total grain boundary area in a fixed-composition system. Similar considerations apply to the grain boundary's excess volume and entropy. For a fixed-volume system, the vacancy concentrations also depend on total grain boundary area, as will the relationship between all concentrations to compositions.
One implication is that the equilibrium phase concentrations and grain boundary excesses must change during grain growth. We examine this behavior's effects by simulation. |