Effect of Directional Solidification on Microstructure Evolution and Mechanical Properties of Eutectic High Entropy Alloy

Directional solidification, as an advanced method for preparing metal materials, can regulate the microstructure and improve the performance of high entropy alloys by controlling the temperature gradient and solidification rate. This study prepared CoCrFeNi3Al1.25 eutectic high entropy alloy (EHEA) at a directional solidification rate of 150 μm/s and investigated the effect of directional solidification rate on microstructure and mechanical properties. Results indicate that directional solidification significantly changes the microstructure, transforming the microstructure from randomly growing microstructure under as cast conditions to eutectic layer structure with a unified growth direction. The tensile strength and elongation of directionally solidified CoCrFeNi3Al1.25 EHEA are 1125.8 MPa and 22.4%, respectively, which are 14.7% and 83.6% higher than the as cast alloy, achieving a synergistic improvement in strength and plasticity.