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

(FeCoCrNi)100-3xTixB2x (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.