| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond V
|
| Presentation Title |
Chemical Disorder in Fe2VAl1-xSix and Its Effect on the Thermoelectric Properties |
| Author(s) |
Fuxiang Zhang |
| On-Site Speaker (Planned) |
Fuxiang Zhang |
| Abstract Scope |
Fe2VAl is a promising thermoelectric intermetallic alloy. The L21 structure undergoes a transformation to B2 structure and BCC solid-solution at high temperatures. The Fe2VAl alloy shows a n-type semiconductor behavior. In this study, the crystal structure and local structure of Si-doped Fe2VAl alloys was studied with synchrotron XRD and EXAFS techniques. The Fe2VAl1-xSix alloy exhibit a L21-type structure till to x=0.15. Surprisingly, both XRD and EXAFS analysis suggest that Si atoms occupy the V sites (4b) in the lattice and partial V atoms share the 4a site with Al. The structure disorder of the alloys and its effect on the thermoelectric properties was quantitatively investigated. Our results demonstrate that chemical order in the L21-structured alloys can be tuned by long-time thermal annealing. The nearly fully ordered intermetallic compound has the highest electric conductivity, and the thermoelectric power can be greatly enhanced. |