Effect of alloyed Ti on the microstructure and corrosion characteristics of a U–Ti alloy in a hydrogen environment

• The formation and growth of uranium hydride sites on U–Ti alloy surface has been investigated.
• Enhanced hydrogen corrosion due to Ti depletion is noticed.
• STEM analysis of the microstructure and chemistry in the decomposed area composed of “α+U2Ti” phase is presented.
• The impact of alloyed Ti on the microstructure and hydriding behavior is given.

The influence of alloyed titanium element on the microstructure and the hydrogen corrosion properties of 500 °C/2 h aged U–0.79 wt.% Ti alloys was investigated. The results demonstrated that 500 °C/2 h aging treatment markedly decreased the hydriding corrosion resistance of U–Ti alloys. The microstructure and chemical compositions of U–0.79Ti alloys exerted a significant influence on the initial hydride nucleation sites and pitting corrosion behavior. A model was proposed to elucidate the formation mechanism of the preferential hydriding on the so-called “α+U2Ti” mixed phase area.