Enhancing Irradiation Resistance of High Entropy Alloys Through FCC-BCC Eutectic Structure

Project: Research

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The development of materials that can withstand even higher doses and temperatures has become the key issue for implementation of advanced reactors. In recent years, high entropy alloys (HEAs) have attracted considerable attentions as potential structural materials due to a good mechanical property, an excellent corrosion and oxidation resistance, and a promising radiation tolerance. Increasing the number of principle elements can effectively reduce the mean free paths of electron and phonon and thus modifies the defect formation and delays defect evolution, leading to an enhanced irradiation resistance. However, the current irradiation studies on HEAs are mostly focused on single-phase (FCC or BCC) materials. The performance of single phase HEAs is still unsatisfactory due to their intrinsic features. FCC alloys are ductile but normally susceptible to void swelling under high dose. BCC alloys are stronger but prone to irradiation induced embrittlement. Naturally, a carefully designed FCC-BCC composite structure could achieve this balance. This proposed research aims to design a class of novel irradiation resistant FCC-BCC eutectic HEAs (EHEAs) which possess a balanced strength and ductility and an improved irradiation resistance. The volume fraction, lamellar spacing, and composition of the two phases will be carefully engineered to achieve a balance between mechanical performance and irradiation resistance. Then the defect evolution under heavy ion irradiation at elevated temperatures will be investigated, especially the effect of phase boundaries will be characterized. The stability of the eutectic structure and the phase stability within each phase will be characterized using a complementary transmission electron microscopy (TEM) and atom probe tomography (APT). Based on systematic experimental studies, the mechanisms of irradiation tolerance of EHEAs will be revealed. The successful fulfillment of this proposal will lead to a comprehensive understanding of the irradiation behaviors of the EHEAs, which is not yet documented. The outcomes will provide an effective guidance for the accelerated design of irradiation resistant HEAs for advanced nuclear applications. 


Project number9043149
Grant typeGRF
Effective start/end date1/01/22 → …