Effects of Ti Content on the Microstructure and Mechanical Properties of Al0.2CoCrFeNi2Tix High-Entropy Alloys

Two high entropy alloys (HEAs) with composition of Al0.2CoCrFeNi2Tix (x = 0.2, 0.4) were prepared through cold rolling and heat treatment to attained favorable mechanical properties and their microstructures were characterized to illustrate the strengthening mechanisms. The results found that the Ti0.4 alloy had high strength (1.34 GPa) via fine grain boundary strengthening and dislocation strengthening, while the existed larger and rod-shaped L1(2) phase caused its limited ductility (10.3%). The Ti0.2 alloy has high strength and plasticity and was superior to the conventional alloys, which was mainly attributed to the nano-sized L1(2) precipitation. The new HEAs are the potential materials to satisfy the needs of contemporary engineering applications and provides reference ideas for designing multi-element metal materials for future applications.