Anisotropic Pitting Of Single-Phase Beta-Zr Alloy And Isotropic Pitting Of Alpha Plus Beta Double-Phase Zr Alloy

Pitting corrosion behaviour of Zr-40Ti-5Al-4 V alloys with different phase composition was investigated. Pitting of the single-phase beta-Zr alloy is crystallographic and the corrosion pits exhibit different orientation, which is mainly attributed to the favored dissolution kinetics of the {001} plane in body-centered cubic beta grains. In contrast, isotropic and circular shaped pitting, due to the evenly distributed alpha and beta phases, was observed in Zr alloy containing alpha + beta double-phase. In addition, weight loss and electrochemical experiments reveal that the double-phase alloy is more sensitive to pitting than the single-phase alloy.