| About this Abstract |
| Meeting |
2021 TMS Annual Meeting & Exhibition
|
| Symposium
|
Defect and Phase Transformation Pathway Engineering for Desired Microstructures
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| Presentation Title |
Pseudo-in situ Characterization of Phase Transformation in an Al-Cu-Mn-Zr Alloy Using Atom Probe Tomography |
| Author(s) |
Bharat Gwalani, Jia Liu, Jonathan Poplawsky, Amit Shyam, Arun Devaraj |
| On-Site Speaker (Planned) |
Bharat Gwalani |
| Abstract Scope |
Aluminum (Al) alloys with improved high-temperature mechanical properties (up to 350oC) are needed to enable the next generation of higher efficiency, affordable vehicle engines. A significant challenge with traditional Al alloys is that at high temperatures the metastable, semi-coherent θ′ (Al2Cu) transforms to θ (Al2Cu), the presence of which deteriorates mechanical properties. The compositionally optimized Al-Cu-Mn-Zr (ACMZ) alloys developed at ORNL can be used at >325oC by utilizing an enveloping co-precipitation around θ′ (Al2Cu) precipitates to extend the θ′ metastability. These co-precipitates could underpin the development of higher performance alloys (375-400oC). The current study investigates the θ′ coherent and semi-coherent interfacial evolution with temperature and time, both compositionally and structurally. To have a detailed understanding of the coprecipitation mechanism, a novel in situ-atom probe tomography (APT) technique coupled with transmission electron microscopy (TEM) were used to probe early stage aging at 300 oC in an ultra-high vacuum environment. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, High-Temperature Materials, Aluminum |