Abstract
A high-entropy dual-phase AlTiVCoNi alloy with a low density of ∼6.24 g cm−3 is developed, and it consists of a hierarchical structure, including an ordered L21 phase, a disordered body-centered-cubic (BCC) solid-solution phase, and nano-sized L21 precipitates embedded in the BCC phase. It is found that this new alloy shows phase stability after the heat treatment at 1200°C for 24 h, and the compressive yield strength of this annealed alloy is approximately equal to that of the as-cast condition, ∼1.6 GPa. This alloy displays an exceptional compressive strength at room temperature and at 600°C, with the specific yield strengths of ∼261 and ∼210 MPa g−1 cm3, respectively. The semi-coherent interface of the L21 and the BCC phases makes the alloy phase stable and regulates the work-hardening mechanism. Local dynamic-recrystallization behavior and grain evolution are observed in the as-prepared alloy during compression at 800 and 1000°C, which results in the high-temperature softening. This alloy with a muti-phase hierarchical structure would provide a new paradigm for the development of next-generation low-density, high-entropy structural materials for high-temperature applications. [Figure not available: see fulltext.].
Original language | English |
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Pages (from-to) | 780-792 |
Number of pages | 13 |
Journal | Science China Materials |
Volume | 66 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2023 |
Externally published | Yes |
Funding
Zhang Y appreciated the supports from the Fundamental Research Funds for the Central Universities (FRF-MP-19-013), Guangdong Basic and Applied Basic Research Foundation (2019B1515120020), the State Key Laboratory for Advanced Metals and Materials, the University of Science and Technology Beijing (2020Z-08), and the Funds for Creative Research Groups of China (51921001) Liao WB thanked the National Natural Science Foundation of China (51801128), and Guangdong Basic and Applied Basic Research Foundation (2021A1515012278 and 2022A1515010288) He Z appreciated the supports from the National Natural Science Foundation of China (51871015 and 52171151) Liaw PK appreciated the supports from the National Science Foundation (DMR-1611180 and 1809640) with program directors, Drs J Yang, G. Shiflet, and D. Farkas and the US Army Research Office (W911NF-13-1-0438 and W911NF-19-2-0049) with program managers, Drs. M.P. Bakas, S.N. Mathaudhu, and D.M. Stepp.
Keywords
- L2 high-entropy intermetallic compound
- hierarchical structure
- high-entropy alloy
- low-density
- specific yield strength