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

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.

Automated summary

High entropy alloys are ideal structural materials with excellent mechanical properties. A novel L12 precipitation strengthened medium entropy alloy is designed, which exhibits a yield strength of 1.09 GPa, an ultimate tensile strength of 1.5 GPa, and nearly 20% elongation at room temperature. However, the fully recrystallized as-aged alloy has poor plasticity at high temperature, while the non-recrystallized alloy directly aged after rolling shows excellent high temperature mechanical properties.