Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 27: Topical Session: Combinatorial Materials Science III

MM 27.1: Topical Talk

Tuesday, March 12, 2013, 15:00–15:30, H25

Bulk Combinatorial Design of nanostructured steels: from composition to mechanisms — Hauke Springer, Ivan Gutierrez-Urrutia, Jae-Bok Seol, Tilmann Hickel, Martin Friak, Jörg Neugebauer, and •Dierk Raabe — Max-Planck-Institut für Eisenforschung, 40237 Düsseldorf, Germany

We present an approach to the high-throughput synthesis of bulk nanostructured steels including the variation of composition and thermomechanical processing. This method, referred to as Rapid Alloy Prototyping (RAP), uses semi-continuous high-throughput casting, rolling, heat treatment and sample preparation. The method is demonstrated on a group of Fe-30Mn-1.2C- x Al steels which exhibits a wide spectrum of structural and mechanical characteristics, depending on the respective Al concentration: High amounts of Al additions (> 8 wt.%) resulted in pronounced strengthening, while low concentrations (< 2 wt.%) led to embrittlement of the material during aging. Of specific interest is the formation and high thermal stability of nanoscaled (5-50 nm) kappa - carbides (L1'2). These precipitates appear in the high Al containing alloy variants (e.g. 8%Al) in the form of highly ordered and coherent particles that have nano-sized solid-solution channels between them. Atom probe analysis and electron microscopy (TEM, ECCI) is conducted to better understand the interaction between these nano-precipitates and dislocations. The stability of the kappa carbides and corresponding compositional trends are also studied using ab initio methods.