About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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Advances in Multi-Principal Elements Alloys X: Structures and Modeling
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Presentation Title |
Microstructural Inversion Accompanied by B2 to hP18 Phase Transformation in a BCC Based Refractory Complex Concentrated Alloy |
Author(s) |
Abhishek Sharma, Sriswaroop Dasari, Vishal Soni, Oleg N. Senkov, Daniel Miracle, Rajarshi Banerjee |
On-Site Speaker (Planned) |
Abhishek Sharma |
Abstract Scope |
A continuous ordered B2 matrix with discrete cuboidal BCC pockets, like a superalloy microstructure, is often observed in RCCAs or RHEAs. Such a microstructure has been attributed to concomitant spinodal decomposition coupled with chemical ordering within the BCC matrix. The Al<sub>0.5</sub>Mo<sub>0.5</sub>NbTa<sub>0.5</sub>TiZr RCCA exhibits this microstructure at the initial stages when annealed at 800°C. Longer term annealing at 800°C results in a phase inversion into a continuous BCC matrix with discrete B2 precipitates. However, these B2 precipitates appear to be a metastable transition phase which eventually transform to an hP18 ordered phase which is a derivative of the ordered ω type structure. This transformation occurs via collapse of the {111} type planes of the parent B2 structure, a phenomenon well reported in other BCC-based alloy systems such as Zr-Al-Nb and Ti-Al-Nb. Here, the compositional and structural changes associated with this transformation, have been characterized using detailed TEM and APT based techniques. |
Proceedings Inclusion? |
Planned: TMS Journal: Metallurgical and Materials Transactions |
Keywords |
High-Entropy Alloys, High-Temperature Materials, Phase Transformations |