Microstructure and grain growth inhomogeneity in austenitic steel produced by wire-feed electron beam melting: the effect of post-building solid-solution treatment

Autor: Marina Yu. Panchenko, Valery E. Rubtsov, Anastasia Sergeevna Fortuna, Valentina Moskvina, Elena G. Astafurova, Evgeny Kolubaev, Sergey V. Astafurov, Kseniya A. Reunova, E. V. Melnikov, Galina G. Maier
Rok vydání: 2020
Předmět:
Zdroj: Journal of Materials Science. 55:9211-9224
ISSN: 1573-4803
0022-2461
Popis: A billet of an AISI 304-type austenitic stainless steel has been built using a wire-feed electron beam additive manufacturing (EBAM) in a layer-by-layer strategy. A microstructure, grain boundary assemble, phase composition and tensile properties of steel billet have been investigated in as-built specimens and after post-built solid-solution treatment. As-built austenitic stainless steel is a highly anisotropic heterophase material with high fraction of interphase boundaries (austenite/ferrite) and intergranular boundaries (austenite/austenite). A macroscopically inhomogeneous (layered) structure with columnar austenitic grain growth has been produced during EBAM processing. The coarse-grained austenitic structure contains δ-ferrite of dendritic morphology in as-built specimens. Ductility and strength properties of the additively manufactured steel show substantial anisotropy, which is strongly correlated with macro- and microstructural peculiarities of the as-built billet. Post-built solid-solution treatment decreases a volume fraction of ferrite in the microstructure, changes the morphology of ferrite phase and, therefore, varies the distribution of interphase boundaries (ferrite/austenite). The effect of post-built solid-solution treatment on tensile properties of the EBAM manufactured steel is discussed taking into account a change in microstructure and phase composition, grain and phase boundary distribution in the specimens.
Databáze: OpenAIRE
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