| 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 |
Thermodynamics and Plastic Deformation in BCC Refractory CCAs |
| Author(s) |
Eric A. Lass |
| On-Site Speaker (Planned) |
Eric A. Lass |
| Abstract Scope |
Refractory-based compositionally-complex alloys (R-CCAs) with the body-centered cubic (BCC) crystal structure have become a promising new class of materials for use in extreme conditions. Among their current shortcomings is the lack of room temperature ductility, a result of the ductile-to-brittle transition exhibited by most BCC alloys. This presentation will examine ductility and plastic deformation in BCC R-CCAs from a thermodynamic perspective. Akin to stacking faults in face-centered cubic (FCC) and hexagonal close-packed (HCP) materials, we show that motion of certain partial dislocations in BCC create local atomic arrangements similar to other crystal structures, such as HCP. Using this concept, the difference in Gibbs free energy between phases is used as a proxy for ductility and experimentally verified in HfTiZr-(Nb,Ta) alloys. Deformation mechanisms, including transformation- and twinning-induced plasticity and conventional dislocation slip, are considered from this perspective. Potential functional forms for the relationship between thermodynamics and dislocation mobility are explored. |