Effect of Spark Plasma Sintering Heating Rate on the Mechanical and In Vitro Corrosion Behavior of Biomedical TiZrNbTaAg High‐Entropy Alloy in Simulated Body Fluid

This study examines the effect of the heating rate during spark plasma sintering (SPS) on the microstructure, microhardness, and electrochemical corrosion behavior of a TiZrNbTaAg high‐entropy alloy (HEA) in simulated body fluid (SBF). The HEA is produced via mechanical alloying and subsequent sintering, employing heating rates of 100, 200, and 300 °C min −1 . Microstructural analysis of the SPS‐consolidated samples reveals the presence of BCC1, BCC2, and Zr‐rich phases. An increase in the heating rate results in enhanced XRD peak intensities and crystallinity. However, this is accompanied by a decrease in both microhardness and relative density as the heating rate increases. At a heating rate of 100 °C min −1 , the alloy exhibits a microhardness of 9.945 GPa and a densification of 99.85%. The dominant phase in all the sintered samples is identified as BCC1. The in vitro corrosion resistance of the SPS samples increases at higher heating rates, indicating that a more stable and protective passive layer is developed in the SBF medium. These results underscore the critical role of optimizing the SPS heating rate to achieve a balance between the processing efficiency and mechanical and electrochemical performance of HEA.