About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Advances in Refractory High Entropy Alloys and Ceramics
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| Presentation Title |
Tensile Creep Mechanisms of the Nb45Ta25Ti15Hf15 and NbTaTiV Refractory High-Entropy Alloys |
| Author(s) |
Mingwei Zhang, Michael Lau, Tamanna Zakia, Gianmarco Sahragard-Monfared, Satish Rao, Wenqing Wang, Calvin Belcher, Mark Asta, Diran Apelian, Enrique Lavernia |
| On-Site Speaker (Planned) |
Mingwei Zhang |
| Abstract Scope |
Tensile creep mechanisms of the Nb45Ta25Ti15Hf15 and NbTaTiV refractory high-entropy alloy (RHEA) were examined at 1173 K under constant true stresses in a high vacuum. Elevated-temperature deformation of Nb45Ta25Ti15Hf15 was identified to be controlled by the cross-kink collision and jog dragging of screw dislocations through TEM characterization. Unlike room-temperature deformation and high-temperature deformation at higher strain rates, kink band formation was not observed during creep deformation. Therefore, a reasonable agreement was obtained while rationalizing the creep deformation of Nb45Ta25Ti15Hf15 using the Rao-Suzuki screw dislocation glide model. However, NbTaTiV shows a disparate creep mechanism of edge dislocation glide control at 1173 K, leading to higher creep resistance and yield strength than Nb45Ta25Ti15Hf15. It is hypothesized that V can induce a higher degree of local lattice distortion that strengthens the material and facilitates a transition from screw to edge dislocation glide control. |