Effect of Si additions on microstructure and properties of TiZrHfNbSix high-entropy alloys as potential biomaterials

Abstract

High-entropy alloys (HEAs) have emerged as promising biomaterials owing to their favorable mechanical properties and resistance to corrosion. This investigation focuses on the impact of incorporating Si on the microstructure and properties of TiZrHfNbSix HEAs. The inclusion of Si leads to the formation of complex compositional silicides, showing multiple structures as the Si content varies. At low Si content, the BCC-silicide eutectic structure blocks the expansion of the shear zone during the deformation process, accounting for the increase in strength. The TiZrHfNbSi0.25 alloy presents a balanced combination of yield strength (∼1129 MPa) and plasticity (∼17 %). Additionally, TiZrHfNbSi0.5 exhibited optimal corrosion resistance in Hank's balanced salt solution (Icorr = 1.713 × 10−7 A cm−2, Ecorr = −0.327 V, 310 K) owing to the reduction in the number of protocells brought about by Si. The remarkable properties of TiZrHfNbSix HEAs renders it a highly promising option for application of silicide reinforcement in biomedical materials.