| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces in Functional Materials: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
Relating Grain Size Distributions and Grain Boundary Excess Coverages to Complexion Transitions in Eu-doped MgAl2O4 |
| Author(s) |
Christopher J. Marvel, Caroline Riedel, Amanda R Krause, Martin P Harmer |
| On-Site Speaker (Planned) |
Christopher J. Marvel |
| Abstract Scope |
A gap in understanding grain boundary complexion transition kinetics is correlating the role of the grain size (i.e. sites for segregation) to the rate of complexion transitions. In this work, Eu-doped MgAl2O4 was synthesized, annealed for multiple temperatures and times, and abnormal grain growth was monitored to construct a complexion time-temperature-transformation (TTT) diagram. Thermally grooved surfaces were characterized to obtain statistically significant grain size distributions, and aberration-corrected electron microscopy was applied to verify differences in grain boundary structure and/or composition in different regions of the TTT diagram. Overall, using atomic-resolution imaging and ζ-factor microanalysis, it was confirmed that increases in grain size led to increases of excess Eu grain boundary coverage. Asymmetric grain boundary complexions were also identified on the abnormal grain boundaries (i.e. ordered on one grain surface but disordered on the abutting grain surface), thereby pinpointing an atomistic mechanism for the vast differences in grain boundary mobility. |