Effect of titanium aluminide coating on cyclic plastic deformation and fatigue life of a titanium alloy at 600 °C

The low cycle fatigue behaviour of titanium alloy IMI 834 was comparatively studied in bare condition and with titanium aluminide coating, at 600 °C in air, for compressor disc of aero engines. At higher values of total strain amplitudes (Δɛt/2), coated alloy has longer fatigue life as compared to the bare alloy which appears to be due to load shifting to the coat, but at lower values of Δɛt/2, coating seems to have no effect on fatigue life. Coating adheres well to the substrate and offers resistance to cyclic plastic deformation and hence is beneficial.

► LCF behaviour of IMI 834 alloy was studied in bare condition and with Al2Ti coating, at 600 °C in air.
► At higher values of Δɛt/2, coated alloy has longer fatigue life as compared to the bare alloy.
► The above phenomenon appears to be due to load shifting to the coat.
► At lower values of Δɛt/2, coating seems to have no effect on fatigue life.
► Coating adheres well and offers resistance to cyclic plastic deformation and hence is beneficial.