Abstract
The devices would subject transient thermal shocks (TTS) during operation under extremely harsh conditions of nuclear fusion reactors, which inevitably exert significant impact on the microstructure and performance of structural materials. In this work, a reduced activation VCrFeTa0.2W0.2 high-entropy alloy (HEA) was developed by vacuum arc melting. The effects of electron beam induced TTS on its microstructure, microhardness, and corrosion properties were investigated. The results indicate that the weight fraction of each phase changes after TTS, showing a significant decrease in the content of BCC1 phase and an increase in the content of BCC2 and Laves phases. The content of BCC1 phase continues to decrease slightly with increasing the power of TTS. Besides, the microhardness of the alloy increases from ~673 HV to ~714 HV after TTS treatments. In the reduced activation HEA, TTS results in a relatively low corrosion current density of ~0.472 μA/cm2 in 3.5 wt% NaCl solution, around one-third of the current density observed in the as-cast sample. Furthermore, the VCrFeTa0.2W0.2 HEA after TTS exhibits a pitting potential of ~1.165 VSCE, which is much higher than that of the as-cast sample. The refined composite multiscale entropy method is employed to analyze the influence of TTS on current fluctuation behavior during the corrosion process. The reduced activation VCrFeTa0.2W0.2 HEA exhibits excellent properties in harsh environments after TTS, thereby showing advantageous property in the field of nuclear structural materials. Moreover, TTS is an efficient and controllable strategy for the improvement of the HEAs’ microstructures and performances.
Original language | English |
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Article number | 165762 |
Journal | Journal of Alloys and Compounds |
Volume | 918 |
DOIs | |
State | Published - Oct 15 2022 |
Funding
This research was supported from the Xi 'an Postdoctoral Innovation Base Project , Fundamental Research Funds for the Central Universities (Grant No. FRF-MP-18-003/ FRF-MP-19-013 ), Key Research and Development Program of Shaanxi (No. 2021GY-249 ), Innovation Center of Nuclear Materials for National Defense Industry ( ICNM-2021-ZH-16 ). W.B.L. would like to thank the National Natural Science Foundation of China (Grant No. 51801128 ), Guangdong Basic and Applied Basic Research Foundation (Grant Nos. 2021A1515012278 and 2022A1515010288 ). J.L.R. would like to thank the National Natural Science Foundation of China (Grant No. 52071298 ). P.K.L. very much appreciates the supports of (1) the U.S. Army Research Office Project ( W911NF-13-1-0438 and W911NF-19-2-0049 ) with the program managers, Drs. M. P. Bakas, S. N. Mathaudhu, and D. M. Stepp and (2) the National Science Foundation ( DMR-1611180 and 1809640 ) with the program directors, Drs. J. Yang, G. Shiflet, and D. Farkas.
Keywords
- Corrosion resistance
- High-entropy alloy
- Microstructure
- Refined composite multiscale entropy
- Transient thermal shock