| About this Abstract |
| Meeting |
2019 TMS Annual Meeting & Exhibition
|
| Symposium
|
Solidification Processing of Light Metals and Alloys: An MPMD Symposium in Honor of David StJohn
|
| Presentation Title |
In Situ Observation of Hyperbranched Dendrites in Aluminum Alloys |
| Author(s) |
Tiberiu Stan, Yue Sun, Kate Elder, Xianghui Xiao, Peter Voorhees |
| On-Site Speaker (Planned) |
Tiberiu Stan |
| Abstract Scope |
When a metal is cooled from the liquid, in nearly all cases from castings to additive manufacturing, the metal freezes via the formation of dendrites. Recent findings indicate that increasing zinc content in Al alloys from ≈25 to ≈55 wt% Zn continuously changes the growth direction from <100> to <110>. Using high temporal and spatial resolution synchrotron x-ray tomography, we present the first in-situ observations of free-growing “hyperbranched” dendrites. The seaweed-like structures have four-fold symmetry with primary arms growing in directions 10 degrees offset from the intersection of {100} planes. The experiments give new information regarding the evolution of dendrite morphologies, tip radii, branch spacings, symmetries, crystallographic growth directions, and interfacial curvatures. Surprisingly, the hyperbranched dendrites exhibit self-similarity during growth. These findings provide insights into the interface energy anisotropy and solidification of Al alloys. |
| Proceedings Inclusion? |
Planned: |