Nano-scale structural evolution of quaternary AlCrFeNi based high entropy alloys by the addition of specific minor elements and its effect on mechanical characteristics

Highlights: • Addition of the Mo and Ti as minor element in the AlCrFeNi high-entropy alloy, enhance the high-temperature hardness. • Nanoscale variations in the morphology and phase formation of the AlCrFeNi HEAs were studied thoroughly. • The minor elements increase the volume fraction of B2 phase and enhance the mechanical properties of the HEAs. -- Abstract: The AlCrFeNi eutectic high entropy alloys have been developed by adding specific minor elements such as 1, 3, 5 at% of Mo and Ti to analyze the mechanical behavior with double phase strengthening. The X-ray diffraction results illustrate that the crystal structure includes dual phases such as B2 and BCC. Regarding on the compositional variation, the formation of eutectic structure was observed by adding minor elements. The detailed investigation of nano structural evolution of the alloy identified that the morphology of nanoscale Al-Ni-rich B2 phase and Cr-Fe-rich A2 phase have a high degree of coherence in dendritic and lamellar regions. As the result of volume fraction changes and variation in grain size on the nanoscale with the addition of minor elements, the enhancement of mechanical properties confirmed the high-temperature hardness behavior of the alloys. In this study, nanoscale features of the AlCrFeNi based HEAs and mechanical characteristics were explored in detail.