The corrosion resistance of magnesium can be improved by modifying the mechanical and chemical properties of the corrosion product film. In this work, the chemical resistance of the corrosion product film is improved by non-equilibrium alloying of magnesium with titanium and yttrium using the process of vapor deposition. The mechanical characteristics of the corrosion product film are improved by bombardment of the alloy with argon atoms. Alloys that have undergone less bombardment due to their deposition at 15 mTorr (2.0 Pa) exhibit lower corrosion rates than alloys that have undergone more bombardment during their deposition at 2 mTorr (0.27 Pa). This process can induce tensile stresses in the alloy and reduce the density of the alloy surface in a manner that enhances the mechanical stability of the corrosion product film. Corrosion rates were reduced and pitting potentials became significantly more noble. Decreasing the corrosion rate of magnesium may expand range of applications for this lightweight, high stiffness material.