About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
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| Symposium
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Microstructural Template Consisting of a Face-Centered Cubic Matrix with Ordered Precipitates: Microstructural Evolution and Properties
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| Presentation Title |
High Temperature Microstructural Stability Mechanisms Revealed by Microscopy in Al-Cu-Mn-Zr Alloys |
| Author(s) |
Jonathan Poplawsky, Patrick Shower, Lawrence Allard, Matthew Chisholm, Dongwon Shin, Amit Shyam |
| On-Site Speaker (Planned) |
Jonathan Poplawsky |
| Abstract Scope |
Typical Al-alloys used for automotive applications can only withstand temperatures of 250C. Retention of a high number density of metastable 𝜃’ precipitates (Al2Cu) is crucial for these alloys’ strength. Recently, ORNL developed an affordable and castable Al-Cu alloy that maintains its strength after a lengthy exposure to 350C (> 200 Hrs). Mn and Zr additions have been shown to be critical for the high temperature stability through a series of atom probe tomography (APT) experiments, scanning transmission electron microscopy (STEM) experiments, and computational simulations. Mn and Zr segregate to both the coherent and semi-coherent 𝜃’ precipitate interfaces. APT was used to calculated interfacial Gibbsian excess that reveal segregation behaviors with time and temperature. The segregation stabilizes the precipitates due to a combined reduction in interfacial energy and solute drag mechanisms. APT was conducted at the CNMS, which is a U.S. DOE Office of Science user facility. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |