Liquid metal embrittlement cracking behavior in iron-zinc (Fe/Zn) couple : Comparison of ferritic and austenitic microstructures

• Liquid metal embrittlement (LME) has emerged as a major concern when developing high-strength automotive steels. However, information regarding the impact of initial microstructure on LME severity is limited in the Fe/Zn couple. Specifically, there is no consensus as to which ferritic and austenitic microstructures are more susceptible to LME cracking. The present study aims to examine the LME cracking behavior of fully ferritic and austenitic microstructures under the same thermomechanical conditions. It was shown that the ferritic microstructure has a higher sensitivity to LME crack initiation, whereas the austenitic specimen displayed a much longer average crack length, which indicates higher crack propagation rate than the ferritic specimen. It has been determined that in-situ austenite to ferrite transformations during Zn diffusion, as well as grain boundary segregation of alloying elements such as Cr and Ti, contribute to the LME propagation rate.

Ämnesord

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

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

Nyckelord

Austenite

Crack initiation

Crack propagation

Ferrite

Initial microstructure

Liquid-metal-embrittlement (LME)

Alloying elements

Grain boundaries

High strength steel

Iron

Liquid metals

Microstructure

Austenitic microstructure

Automotive steels

Cracking behavior

Cracks initiations

Cracks propagation

Ferritic microstructure

High-strength

Initial microstructures

Liquid metal embrittlement

Liquid-metal-embrittlement

Publikations- och innehållstyp

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