Self-ion irradiation response of (CoCrFeNi)₉₄Ti₂Al₄ alloy containing coherent nanoprecipitates

In order to investigate the impact of coherent nanoprecipitates on the irradiation-induced microstructural change in high-entropy alloys and the stability of nanoprecipitates under irradiation, the single-phase CoCrFeNi and the coherent nanoprecipitate-containing (CoCrFeNi)₉₄Ti₂Al₄ alloys were irradiated with 2.7 MeV Fe ions at 823 K. With the introduction of L1₂ coherent nanoprecipitates, the size of irradiation-induced dislocation loops is significantly reduced and the unfaulting of faulted loops is delayed. Unlike that both Ni and Co are segregated towards the loops in CoCrFeNi, the enrichment of Ni at loops is suppressed in (CoCrFeNi)₉₄Ti₂Al₄ with the co-existence of nanoprecipitates. Furthermore, although minor coarsening and dissolution of nanoprecipitates are observed after irradiation, the stability is enhanced compared with some conventional Ni-based alloys.