Microstructural and mechanical properties of non-equimolar NiCoFeAlTi medium entropy alloy strengthening by L12 nanoparticles

Abstract

Ideal structural materials usually require excellent mechanical properties, high entropy alloys/medium entropy alloys (HEAs/MEAs) are considered to be the key material to achieve this goal. In the current work, a novel L12 precipitation strengthened medium entropy alloy is designed. After rolling and recrystallization, the alloy which is then aged possesses a mechanical property of a yield strength of 1.09 GPa, an ultimate tensile strength of 1.5 GPa and nearly 20% elongation at room temperature (the as-aged alloy). However, the plasticity of the as-aged alloy which is fully recrystallized is poor at high temperature. Then, the non-recrystallized alloy, which is directly aged after rolling, containing coarse lengthening grain with lower grain boundary energy, exhibits excellent high temperature mechanical properties.