Dataset Information

Superplasticity in a lean Fe-Mn-Al steel.

ABSTRACT: Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here we introduce a new compositionally lean (Fe-6.6Mn-2.3Al, wt.%) superplastic medium Mn steel that resolves these limitations. The medium Mn steel is characterized by ultrafine grains, low material costs, simple fabrication, i.e., conventional hot and cold rolling, low deformation temperature (ca. 650?°C) and superior ductility above 1300% at 850?°C. We suggest that this ultrafine-grained medium Mn steel may accelerate the commercialization of superplastic ferrous alloys.Research in new alloy compositions and treatments may allow the increased strength of mass-produced, intricately shaped parts. Here authors introduce a superplastic medium manganese steel which has an inexpensive lean chemical composition and which is suited for conventional manufacturing processes.

SUBMITTER: Han J

PROVIDER: S-EPMC5622104 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Superplasticity in a lean Fe-Mn-Al steel.

Han Jeongho J Kang Seok-Hyeon SH Lee Seung-Joon SJ Kawasaki Megumi M Lee Han-Joo HJ Ponge Dirk D Raabe Dierk D Lee Young-Kook YK

Nature communications 20170929 1

Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here ...[more]

PMID: 28963494

Similar Datasets

Project description:High Al Low-density steels could have a transformative effect on the light-weighting of steel structures for transportation. They can achieve the desired properties with the minimum amount of Ni, and thus are of great interest from an economic perspective. In this study, the mechanical properties of two duplex low-density steels, Fe-15Mn-10Al-0.8C-5Ni and Fe-15Mn-10Al-0.8?C (wt.%) were investigated through nano-indentation and simulation through utilization of ab-initio formalisms in Density Functional Theory (DFT) in order to establish the hardness resulting from two critical structural features (?-carbides and B2 intermetallic) as a function of annealing temperature (500-1050?°C) and the addition of Ni. In the Ni-free sample, the calculated elastic properties of ?-carbides were compared with those of the B2 intermetallic Fe3Al-L12 and the role of Mn in the ? structure and its elastic properties were studied. The Ni-containing samples were found to have a higher hardness due to the B2 phase composition being NiAl rather than FeAl, with Ni-Al bonds reported to be stronger than the Fe-Al bonds. In both samples, at temperatures of 900?°C and above, the ferrite phase contained nano-sized discs of B2 phase, wherein the Ni-containing samples exhibited higher hardness, attributed again to the stronger Ni-Al bonds in the B2 phase. At 700?°C and below, the nano-sized B2 discs were replaced by micrometre sized needles of ? in the Ni-free sample resulting in a lowering of the hardness. In the Ni-containing sample, the entire ? phase was replaced by B2 stringers, which had a lower hardness than the Ni-Al nano-discs due to a lower Ni content in B2 stringer bands formed at 700?°C and below. In addition, the hardness of needle-like ?-carbides formed in ? phase was found to be a function of Mn content. Although it was impossible to measure the hardness of cuboid ? particles in ? phase because of their nano-size, the hardness value of composite phases, e.g. ??+?? was measured and reported. All the hardness values were compared and rationalized by bonding energy between different atoms.

Project description:In this paper, analytical results are compared for the newly developed steels, Fe-Mn-Al-C (X105) and Fe-Mn-Al-Nb-Ti-C (X98), after being hot-rolled and also after undergoing thermomechanical treatment in a Gleeble simulator. These steels have a relatively low density (~6.68 g/cm3) and a content of approx. 11% aluminum. The multistage compression of axisymmetric samples constituting a simulation of the real technological process and hot-rolling performed on a semi-industrial line were carried out using three cooling variants: in water, in air, and after isothermal heating and cooling in water. The temperature at the end of the thermomechanical treatment for all variants was 850 °C. On the basis of detailed structural studies, it was found that the main mechanism for removing the effects of the strain hardening that occurred during the four-stage compression involved the dynamic recrystallization occurring in the first and second stages, the hot formability and dynamic recovery in successive stages of deformation, and the static and/or metadynamic recrystallization that occurred at intervals between individual deformations, as well as after the last deformation during isothermal heating. Analysis of the phase composition and structure allowed us to conclude that the tested steels have an austenitic-ferritic structure with carbide precipitates. Research using scanning and transmission electron microscopy identified ?-(Fe, Mn)3AlC and M7C3 carbides in both the analyzed steels. In addition, complex carbides based on Nb and Ti were identified in X98 steel; (Ti, Nb)C carbides occurred in the entire volume of the material. Slow cooling after thermomechanical treatment influenced the formation of larger ?-carbides at the border of the austenite and ferrite grains than in the case of rapid cooling. The size and morphology of the carbides found in the examined steels was varied. Back-scattered electron diffraction studies showed that wide-angle boundaries dominated in these steels.

Dataset Information

Superplasticity in a lean Fe-Mn-Al steel.

Publications

Superplasticity in a lean Fe-Mn-Al steel.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets