|About this Abstract
||3rd World Congress on High Entropy Alloys (HEA 2023)
||Defect Mediated Microstructural Evolution and Phase Transformations in a BCC Based Al<sub>0.5</sub>NbTa<sub>0.8</sub>Ti<sub>1.5</sub>V<sub>0.2</sub>Zr Refractory High Entropy Alloy
||Abhishek Sharma, Advika Chesetti, Tirthesh Ingale, Vishal Soni, Hamish Fraser, Stéphane Gorsse, Rajarshi Banerjee
|On-Site Speaker (Planned)
This study focuses on how prior deformation influences the phase transformation pathway and the resultant microstructural evolution in the BCC-based Al<sub>0.5</sub>NbTa<sub>0.8</sub>Ti<sub>1.5</sub>V<sub>0.2</sub>Zr refractory high entropy alloy (RHEA). The solutionized alloy was cold-rolled prior to annealing, which resulted in an extremely refined HCP-based ordered omega phase dispersed within a disordered BCC matrix. This microstructure is in contrast to the B2+BCC microstructure that forms when this alloy is annealed at the same temperature, a transformation pathway which has been previously reported. Presence of deformation substructure consisting of dislocations, twins, etc. provides a high number density of heterogenous nucleation sites distributed within the matrix resulting in a lower nucleation barrier for crystallographically mismatched phases such as the hexagonal ordered omega phase. The compositional and structural changes associated with the ordered omega precipitation, were characterized in detail by TEM and APT, and provide insights for microstructural design of RHEAs.
||Planned: Metallurgical and Materials Transactions