Characteristics and Sintering Behavior of (Hf-Ta-Ti-Zr-Nb)C High-Entropy Carbides Fabricated by High-Energy Ball Milling and Spark Plasma Sintering

The present study aimed to analyze the sintering behavior and mechanical properties of (Hf-Ta-Ti-Zr-Nb)C highentropy carbide powder fabricated using an ultra-high-energy ball mill. The fabricated powder was sintered by means of spark plasma sintering (SPS) at a constant pressure of 50 MPa and for ten minutes with varying sintering temperature between 1700, 1800, and 1900 & DEG;C. Changes in the microstructure and mechanical properties of the powder and sintered carbides were examined. The high-entropy carbide powder obtained after 60 minutes of ball milling was found to be an assembly of uniformly distributed particles with a size of hundreds of nanometers. It was also found that the degree of X-ray line broadening increased with increasing milling time. When the milling time was relatively long, that is 60 minutes, the elements that initially existed in the form of multi-carbides tended to merge as part of a single FCC phase. In addition, an increase in the temperature of the spark plasma sintering process was found to help to improve the sintering density and hardness. This result confirmed that the temperature change was one of the most important process parameters that determined the degree of densification of sintered high-entropy carbides.