Effect of In Situ TiC Formation and Direct TiN Addition on the Microstructure and Mechanical Properties of CoCrFeNi-Based High-Entropy Alloys

CoCrFeNi-based high-entropy alloys (HEAs) have shown great potential for widespread applications in aerospace, chemical, and medical equipment fields due to their high strength, wear resistance, corrosion resistance, and thermal stability. In the present study, a series of Ni2CoCrFeVxCuy alloys were designed to obtain a ductile FCC matrix suitable for ceramic-particle reinforcement. Subsequently, two representative reinforcement strategies, namely, in situ TiC formation and direct TiN nanoparticle addition, were employed to investigate their effects on the microstructure and mechanical properties of the alloy. The results showed that Ni2CoCrFeV0.5Cu0.2 exhibited the best strength–ductility balance, with a tensile elongation of 51.8% among the designed alloys. Besides, the comprehensive performance of high-entropy alloys can be effectively enhanced by in situ generation of TiC and addition of TiN particles. The in situ synthesized TiC exhibited a finer and more uniform distribution than the directly added TiN particles, resulting in a more favorable strength–ductility balance under the present processing conditions.