Hydrogen embrittlement is the process by which hydride-forming metals such as titanium, vanadium, zirconium, tantalum, and niobium become brittle and fracture due to the introduction and subsequent diffusion of hydrogen into the metal. Hydrogen embrittlement is the process by which hydride-forming metals such as titanium, vanadium, zirconium, tantalum, and niobium become brittle and fracture due to the introduction and subsequent diffusion of hydrogen into the metal.