Synergistic effect of Ti and Al on L12-phase design in CoCrFeNi-based high entropy alloys

L12-phase-strengthened high entropy alloys (HEAs) have shown promising mechanical properties for both high-temperature and cryogenic applications. However, designing L12 phase still strongly relies on the trial-and-error experiments. The current study reported that the L12 phase in face centered cubic (FCC) HEAs is greatly influenced by a sygnergistic effect of Ti and Al. The experimental results showed that a Ti/Al ratio ranging from 0.7 to 2 was required by L12 phase in CoCrFeNi-based HEAs. The present findings provided an efficient guideline for designing L12 phase in the complex concentrated alloys. •The relative contents of Ti and Al play a critical role in the formatiom of L12-phase.•The Ti/Al ratios ranging from 0.7 to 2 would prefer the formation of L12 phase in the CoCrFeNi-based HEAs.•In the complex FCC alloy systems, Ti is a main L12 phase former and Al is a L12 phase stabilizer.