The influence of high-temperature oxidation resistant titanium aluminide coating on low-cycle fatigue behaviour of titanium alloy IMI 834 at 600°C

Abstract

The low-cycle fatigue behaviour of titanium alloy IMI 834 was comparatively studied in bare condition and with titanium aluminide (Al2Ti) coating at 600°C in air. Results revealed that at higher values of total strain amplitudes (Δε t/2), Al2Ti-coated IMI 834 alloy has longer fatigue life (N f) compared to the bare IMI 834 alloy, which appears to be due to load shifting to the coat. At lower values of Δε t/2, Al2Ti coating on IMI 834 alloy seems to have no effect on N f. Higher values of cyclic strength coefficient (K′) and cyclic hardening exponent (n′) for coated IMI 834 alloy indicate that coating offers resistance to cyclic plastic deformation at 600 °C in air, and hence it is beneficial. The coating adheres well to the substrate and is also fairly resistant to high-temperature corrosion in sea water atmosphere at 600 °C.