AlCuFe(Cr) and AlCoFeCr coatings for improvement of elevated temperature oxidation resistance of a near-a. titanium alloy

摘要

In this work, an AlCuFe, AlCuFeCr and AlCoFeCr multicomponent coatings were deposited on a near-α titanium alloy, TIMET AL 834, by a non-reactive magnetron sputtering. A microstruc-ture, phase composition, coatings adhesion to the substrate, micro-mechanical properties and oxidation resistance were investigated. The AlCuFe coating was quasicrystalline and consisted of icosahedral Ψ-Al_(65)Cu_(20)Fe_(15) phase grains. The AlCuFeCr coating consisted mainly of decagonal d-AlCuFeCr phase and some Al_(6.1)Cu_(1.2)Ti_(2.7) phase grains. The AlCoFeCr coating microstructure was composed of AlCrFe_2 nanocrystals embedded in an Al_(13)Co_4 matrix. It was established that all multicomponent coatings exhibit higher hardness and elastic moduli than the titanium alloy substrate. Among all investigated coatings, the AlCoFeCr one exhibits the best adhesion to the substrate.