Corrosion resistance of Ti-6246 for high power aeroengine compressor discs and blades

Abstract

The corrosion resistance between 723 and 1123 K of Ti-6246 has been investigated. For temperatures between 723 and 823 K, the maximum weight gain in air was below the measurable range. For the temperature range 873–1123 K, there was substantial weight gain with reaction time with a maximum weight gain of 180×10^-4 g cm^-2 being obtained after 150 h at 1123 K. Weight gain for the vacuum tests remained constant over all temperatures and reaction times with a maximum observed increase of 3×10^-4 g cm^-2. There was evidence in favour of parabolic rather than linear increases in weight gain with time. The parabolic and linear rate constants increased with temperature and the activation energy associated with parabolic oxidation was estimated as 216 kJ mol^-1. The life of Ti-6246 in argon at 773 K was found at certain stresses to be almost twice that obtained in air. This difference could not be explained by the loss of load bearing cross-sectional area following oxidation.