The Effect of Secondary Phase on Corrosion Behaviors of the Titanium–zirconium–molybdenum Alloy

As the range of applications for molybdenum and its alloys has expanded, the corrosive environment for molybdenum alloys has become more demanding. In the past, the content of doping elements has been studied to investigate their influence on the corrosion performance of titanium–zirconium–molybdenum (TZM) alloys. In this paper, it is considered that the second phase in the alloy is the main factor affecting the corrosion performance of TZM alloys. By comparing the corrosion behavior of molybdenum metal and TZM alloy, the effect of the secondary phase on corrosion behaviors of TZM alloy has been investigated. The results show that the second phase reduces the corrosion resistance of the TZM alloy. The potential of the second phase is 73.7 mV higher than that of the Mo matrix, which contributes to the formation of microscopic electric couples. Under the action of microscopic electric couples, pitting corrosion is preferentially formed at the interface between the second phase and the matrix, which accelerates the corrosion of the matrix. This paper provides a theoretical basis for the application of TZM alloys in corrosive environments.