Intergranular oxidation of additively manufactured Ni-base alloy 625: The role of Si

• Additively manufactured (AM) Ni-base alloy 625 exposed in air and H2/H2O at 900 °C has been shown to suffer from intergranular oxidation attack unlike its conventionally manufactured (CM) variant. Modification of the AM microstructure via hot-rolling and heat-treatment did not alter the oxidation pattern. Detailed analysis of minor differences in chemical composition of AM and CM exposed the critical role of Si in oxidation protection of alloy 625. Experiments with model alloys as well as diffusion modeling confirmed the crucial role of a minimum Si concentration to form a SiO2 subscale preventing thereby intergranular oxidation attack.

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

High-temperature corrosion

Alloy 625

Intergranular oxidation

Additive manufacturing

Oxidation

Ni-base alloys

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