Effect of Ti and B additions on the microstructure and properties of FeCoCrNi high entropy alloys prepared by hot pressing

Abstract

(FeCoCrNi)_100-3xTi_xB_2x (x = 0, 1, 2 and 6 at.-%) high entropy alloys (HEAs) were fabricated by hot pressing. The effects of Ti and B content on the microstructure and mechanical properties were investigated using X-ray electron diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results show that the FeCoCrNi high-entropy alloy form single FCC phase. With the increase of Ti and B content, dual FCC phases appeared in the alloys. Additionally, the per cent elongation of alloys first increased and then declined, while the ultimate tensile strength kept moving up. The (FeCoCrNi)₉₇TiB₂ alloy has the highest per cent elongation of 13.1%, which is more than three times that of the FeCoCrNi. the (FeCoCrNi)₈₂Ti₆B₁₂ alloy shows the highest ultimate tensile strength, which is 646.5 ± 0.1 MPa. The enhanced strength is attributed to solid solution effect and Orowan process.