Alloy Design, Combinatorial Synthesis, and Microstructure–Property Relations for Low-Density Fe-Mn-Al-C Austenitic Steels

Abstract

We present recent developments in the field of austenitic steels with up to 18% reduced mass density. The alloys are based on the Fe-Mn-Al-C system. Here, two steel types are addressed. The first one is a class of low-density twinninginduced plasticity or single phase austenitic TWIP (SIMPLEX) steels with 25-30 wt.% Mn and <4-5 wt.% Al or even <8 wt.% Al when naturally aged. The second one is a class of j-carbide strengthened austenitic steels with even higher Al content. Here, j-carbides form either at 500-600°C or even during quenching for >10 wt.% Al. Three topics are addressed in more detail, namely, the combinatorial bulk high-throughput design of a wide range of corresponding alloy variants, the development of microstructure-property relations for such steels, and their susceptibility to hydrogen embrittlement. INTRODUCTION TO LOW DENSITY STEELS

Deformation mechanisms for superplastic behaviors in a dual-phase high specific strength steel with ultrafine grains

“…Such expectations have been realized in recent decades by low-density steels, which are mainly based on FeAl-Mn-C alloy system and are so called TRIPLEX steels. These TRIPLEX steels generally consist of fcc austenite, bcc ferrite and finely dispersed nanometer-sized κ-carbides with (Fe, Mn) AlC 3 type [17][18][19][20][21][22][23]. More recently, Kim et al [24] has developed a high specific strength steel (HSSS) with composition of Fe-16Mn-10Al-0.86C-5Ni (weight %), which consists of both fcc austenite phase and intermetallic compound B2 phase.…”

Identifying Structure–Property Relationships Through DREAM.3D Representative Volume Elements and DAMASK Crystal Plasticity Simulations: An Integrated Computational Materials Engineering Approach

“…3,4 Like other modern high-performance alloys, HMnS combine multiple deformation mechanisms to overcome the inverse strength-ductility relationship. 5,6 Besides dislocation glide, both, transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP), serve as additional deformation mechanisms. 7,8 From an engineering point of view, additional deformation mechanisms create the challenge that they are influenced by several microstructural and environmental parameters such as grain size, texture, chemical composition, temperature, strain rate, and the nonlinear interactions between them.…”

Strain Rate Effect on Tensile Behavior for a High Specific Strength Steel: From Quasi-Static to Intermediate Strain Rates

“…Recently, high specific strength steels (HSSS) with low density, achieved by adding Al (3-12 wt. %), have been widely studied due to their excellent mechanical properties, such as high specific yield strengths and large uniform elongations [8][9][10][11][12][13][14][15][16][17][18][19]. Most of these HSSS are based on Fe-Al-Mn-C alloy system (so called TRIPLEX steels), and consist of fcc austenite matrix, bcc ferrite matrix and finely dispersed κ-carbides ((Fe, Mn) 3 AlC.…”