Microstructures and mechanical properties of AlxCrFeNiTi0.25 alloys

Aiming to lower the cost and improve mechanical properties of AlCoCrFeNiTix high-entropy alloys that were studied previously, the present research investigated the effect of removing Co and lowering Ti contents at various Al contents, namely AlxCrFeNiTi0.25. The microstructures were investigated using optical microscopy, scanning electron microscopy, energy disperse spectroscopy, X-ray diffraction and transmission electron microscopy. Compression tests were conducted at room temperature. The present study showed that with increasing Al contents, the phase structures of the alloys changed from FCC + BCC to double BCC as the main phases. Among the alloys studied, all of them exhibit distinguished work hardening. Especially the Al0.5CrFeNiTi0.25 alloy has the highest fracture strength and plastic-strain limit of 3.47 GPa and 40%, respectively with a yield strength of 1.88 GPa. The observed microstructure is analyzed using CALPHAD calculations.