Microstructure, mechanical and high temperature properties of cast high Mn low-density steels alloying by small Lanthanum additions.

[Display omitted] • Small La additions refines the crystal microstructure of Fe-Mn-Al-C steel. • The Al 2 O 3 based oxide scale prevents the further diffusion of oxygen into the steel. • The cast Fe-Mn-Al-C steels have high ultimate tensile strength and oxidation resistance. An influence of La additions on microstructure, mechanical properties and high temperature oxidation of Fe-20Mn-12Al-1C (wt %) triplex steels has been investigated. It was shown that the melt modification with small lanthanum additions (0.1 wt %), not only purifies melt and refines the ferrite grains during crystallization, but also increases the oxidation resistance of steel. The uniform dense oxide film formation mainly consisted of Al 2 O 3 on the alloy/oxide scale interface, which better prevents the further diffusion of oxygen into the steel and protects it. Cast steels Fe-20Mn-12Al-1C have ultimate tensile strength (UTS) of >1 GPa and high oxidation resistance at the same time. [ABSTRACT FROM AUTHOR]