| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces in Ceramics: Fundamental Structure—Property—Performance Relationships
|
| Presentation Title |
Abnormal Grain Growth in Nanocrystalline PdAu: The Case of the Fractal Fingerprint |
| Author(s) |
Raphael A. Zeller, Markus Fischer, Christian Braun, Mingyan Wang, Rainer Birringer, Carl E. Krill |
| On-Site Speaker (Planned) |
Carl E. Krill |
| Abstract Scope |
In most polycrystalline materials, coarsening tends to be a civilized affair, with adjacent grains taking pains to exchange atoms so as to maintain a smooth boundary. The grains that grow in nanocrystalline PdAu, however, behave like uncouth neighbors crashing a fancy dinner party: once they get revved up, all hell breaks loose! Before you know it, a few nanometer-sized grains have grown four orders of magnitude in diameter, and the resulting interfaces are so convoluted that they resemble fractal objects. Our usual notion of curvature-driven grain boundary migration fails to explain the persistence of these interfacial fluctuations, but recent experiments find the onset of fractality to depend on the Au concentration as well as on a characteristic length scale. We consider this evidence to be a kind of “fractal fingerprint” that, ultimately, incriminates a specific mechanism as the responsible party for the system’s abnormal grain growth. |