The microstructural evolution in V + 14.7 Cr, V + 2.5 Mo, V + 2.5 W, V + 8.0 Ni, V + 5.3 Ti, V + 14.7 Cr + 5.2 Ti, V + 9.6 Cr + 3.1 Fe + 0.7 Zr, and V + 3.2 Ti + 1.8 Si alloys (concentrations in atomic percent), and unalloyed V was determined from observations of specimens by transmission electron microscopy (TEM) following 4.0-MeV ⁵¹V⁺⁺ ion irradiation at 900 to 970 K to 50 dpa. The radiation-induced segregation (RIS) of solutes in the ion-irradiated alloys was investigated by auger electron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDXS), and electron energy loss spectroscopy (EELS) analyses. The RIS of solutes and microstructural evolution in the irradiated alloys were correlated with the solute diffusivity and the relative chemical affinity of the substitutional solutes for oxygen.