Oxidation behaviour of IMI834 and Ti-1100 alloys at high temperature of 550°C - 750°C

The oxidation kinetics has been studied for IMI834 and Ti-1100 high temperature titanium alloys at temperature range of 550°C to 750°C in air. The structure, profile and composition of oxide layer were examined by X-ray diffraction, scanning electron microscopy and electron probe microanalysis. The experimental results .reveal that both IMI834 and Ti-1100 titanium alloys exhibit parabolic oxidation rate law at temperature range of 600°C - 750°C. Al ₂O ₃ protective film formed on the outer surface of TiO ₂ oxide layer obstructs the penetration of oxygen and reduces oxidation rate. Nb element in IMI834 alloy is favorable to improve the nature of oxide layer, and increases the oxidation resistance of the alloy at high temperature. The oxygen absorbed in alloy at oxidation, except for forming TiO ₂ oxidation layer, dissolves into the matrix and forms the surface oxygen-enriched layer which becomes an important factor decreasing the thermal stability of the high temperature titanium alloy.