Oxidation resistance of nanocrystalline microalloyed γ-TiAl coatings under isothermal conditions and thermal fatigue

γ-Titanium aluminide is a promising structural material for use in automotive and aircraft applications due to its low density and creep and a relatively high strength even at the temperature as high as 1200 K. Nevertheless, its resistance to gas corrosion at high temperatures still needs to be improved. It has been proved in the work by means of SEM, EDS, EBSD, X-ray and microthermogravimetric analyses under isothermal conditions at 1173 K and thermal fatigue in the interval 373 ÷ 1173 K that a great improvement of this resistance can been achieved due to γ-TiAl-based magnetron sputtered coatings with ternary or quaternary elements from Ag, Cr, Mo, Nb, Si, Ta or W: the parabolic rate constants of the oxidation of some coatings are five orders of magnitude less than that of the bare γ-TiAl substrate.