Abstract
Refractory high-entropy alloys (RHEAs) are considered promising candidate materials for high-temperature structural applications that currently use superalloys. However, for most of the reported RHEAs, their poor ductility and negligible cold-workability at room temperature have hindered their use. Here, we report a new class of non-equiatomic NbTaTi-based RHEAs that can be cold-rolled to a reduction of over 90% from the as-cast state without surface treatment and/or intermediate annealing. This excellent cold-workability is facilitated by activation of a high-density of dislocations and deformation twins as well as by high diffusivity paths, such that these RHEAs can be rendered homogeneous at lower annealing temperatures for much shorter time durations. In addition, we report that the RHEAs retain their high strength at elevated temperatures and exhibit considerable ductility at cryogenic conditions, evading the traditional strength–ductility trade-off. This class of super-formable RHEAs provides a novel design pathway to fabricate high-temperature structural materials via an energy- and time-saving method.
Original language | English |
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Article number | 118602 |
Number of pages | 11 |
Journal | Acta Materialia |
Volume | 245 |
Early online date | 8 Dec 2022 |
DOIs | |
Publication status | Published - 15 Feb 2023 |
Bibliographical note
Acknowledgments:C.Z., BEM and E.J.L. would like to acknowledge financial support from UCI. This research was also partially supported (EJL, X.W., BEM and TJR) by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967). Xinyi W. and P.C. acknowledge financial support from National Science Foundation (DMR-2105328, CMMI-1935371). We also would like to thank Dr. Fan Ye, Dr. Li. Xing, and Dr. Jian-guo Zheng (IMRI, UC Irvine) for TEM assistance. We acknowledge Dr. Mingde Qin and Xiao Liu (UC San Diego) for assistance in some experiments.
Keywords
- Refractory high-entropy alloys
- Formability
- Cryogenic-to-elevated temperatures
- Strength-ductility synergy