AbstractThe interaction of unalloyed vanadium with carbon, oxygen, nitrogen, and hydrogen and the effects of these elements on the mechanical behaviour of vanadium and vanadium alloys are reviewed. Hydrogen, nitrogen, and oxygen exhibit high solid solubility (≥2 at.-% at 500°C) while carbon solubility in vanadium is less than O. 1 at.-% at 500°C. Vanadium containing less than 150 ppm by weight of oxygen is ductile in bending at −196°C. Adding 1600 ppm oxygen or 850 ppm nitrogen raises the temperature for ductile behaviour to +25°C and +150°C, respectively. As little as 10 ppm by weight of hydrogen causes brittle fracture in vanadium at −100°C. Few data are available on gas-metal interactions with vanadium alloys and the effects on time':,dependent and time-independent deformation. Limited data indicate that the creep-rupture life of a vanadium alloy containing Cr-Fe-Zr and C is altered by a factor of >5 when test pressures are change from 6 × 10-4 to 6 × 10-7 Pa.