Unique dislocation loops distribution of AlCrFeNiTix eutectic high-entropy alloys under high-temperature ion irradiation

Eutectic high-entropy alloys (EHEAs) have drawn great attention due to their excellent high-temperature mechanical properties. A group of EHEAs AlCrFeNiTix with different titanium contents was irradiated with 3 MeV Fe11+ ions at 500 degrees C with fluences of 9.1 x 1014 and 4.55 x 1015 ions/cm2. The disordered body -centered-cubic (BCC, A2) exhibited smaller-sized dislocation loops than those of ordered BCC (B2) based on Transmission electron microscopy (TEM) analysis. The type of loops found in AlCrFeNi alloy were < 100 > and 1/2 < 111 > . The fraction of 1/2 < 111 > was higher, indicating the excellent irradiation resistance of EHEAs. Small size and large density of dislocation loops formed after the addition of Ti. Phase boundaries in the alloys could effectively decrease the density and size of dislocation loops because of defects annihilation at phase boundaries. In combination with density function theory (DFT) results. B2 phase exhibited better energy landscape advantage in the Ti accommodating, and the MSD results indicated that the lattice dis-tortion effect caused by Ti entering B2 phase was more obvious than A2 according to the density function theory (DFT) results. Our research exhibited a beneficial scheme for solid solution strengthening of ele-ments in EHEAs, and provided an insight into the suppression of dislocation loops under irradiation. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In this research, EHEAs AlCrFeNiTix with different titanium contents were irradiated, and it was found that phase boundaries effectively decreased the density and size of dislocation loops, while the addition of titanium resulted in small-sized and high-density dislocation loops. Density function theory (DFT) results showed that the B2 phase was more suitable for accommodating titanium, and the lattice distortion effect caused by titanium in the B2 phase was more obvious than in the A2 phase. This study provides a beneficial scheme for solid solution strengthening of elements in EHEAs and offers insights into the suppression of dislocation loops under irradiation.