Impeding the γ' depletion during the interdiffusion between bond coatings and superalloys via introduction of tantalum in bond coatings

• The use of aluminiferous coatings profoundly improves the service life of superalloys but leads to microstructural degradation of superalloys and thus loss of mechanical properties. In this study, we mod- ified MCrAlY coatings by adding Ta to reduce the interdiffusion effect on substrate alloys. This strategy was verified by 2000 h/1100 °C oxidation tests in two Ta-containing MCrAlY-IN792 systems. The system with 3.3 wt% Ta MCrAlY exhibits an outstanding resistance to c0 depletion in the substrate and compa- rable oxidation property in comparison with a reference system of Ta-free MCrAlY-IN792. Increasing Ta to 7.4 wt% results in reduced oxidation resistance. Thermodynamic simulations revealed the phase- transformation mechanism induced by initial interdiffusion, uncovering the cause of c0 depletion in the substrate and the mechanism behind improving resistance to c0 depletion by Ta addition.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Bonding coating; Interdiffusion; Microstructural degradation; Thermodynamics

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