Combinatorial design of transitory constitution steels: Coupling high strength with inherent formability and weldability through sequenced austenite stability

Springer, Hauke; Belde, Michael Martinus; Raabe, Dierk

doi:10.1016/j.matdes.2015.11.050

Cited by 26 publications

(16 citation statements)

References 25 publications

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“…Non-equilibrium segregation engineering through vessel phases: Tailored austenite retention around partially dissolved precipitates Another approach to the utilization of confined transformation zones consists in the deliberate introduction of site specific and geometrically confined non-equilibrium segregation zones. This microstructure design method is based on the utilization of so-called vessel phases, which were recently introduced and applied to the design of austenite in multiphase steel microstructures [5][6][7]25 Figure 9. Bone like fatigue resistance observed in a nano-laminate martensite-austenite steel.…”

Section: Figurementioning

confidence: 99%

“…The size and stability of these austenitic zones can be adjusted by tuning the diffusional fluxes during the dissolution treatment. The figure has been adapted from Belde et al [5][6][7]25].…”

Section: Figurementioning

confidence: 99%

“…Alternatively, it is also conceivable to exploit such effects for the case of non-equilibrium compositional gradients that are inherited either from a Scheil-type solidification inhomogeneity or from incomplete intercritical phase dissolution [5][6][7]. Such scenarios, which are based on kinetically acquired compositional inhomogeneities, are referred to as non-equilibrium segregation engineering.…”

Section: Introduction To the Segregation Engineering Principlementioning

confidence: 99%

“…The thermodynamic rules include the requirement to consider also the competition with the formation of alternative phases in the bulk matrix (rather than being confined to specific defects), the consideration of the equilibrium or non-equilibrium segregation coefficients, co-segregation effects, phase stability (relevant when designing confined states that can undergo spatially confined athermal phase transformations), as well as the interplay of chemical and mechanical driving forces [1-4]. The kinetic rules include consideration of the diffusion coefficients as well as of thermal versus diffusional phase transformation pathways [5][6][7]. Figure 1.…”

Section: Introduction To the Segregation Engineering Principlementioning

confidence: 99%

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1 billion tons of nanostructure – segregation engineering enables confined transformation effects at lattice defects in steels

Raabe

Ponge

Wang

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The microstructure of complex steels can be manipulated by utilising the interaction between the local mechanical distortions associated with lattice defects, such as dislocations and grain boundaries, and solute components that segregate to them. Phenomenologically these phenomena can be interpreted in terms of the classical Gibbs adsorption isotherm, which states that the total system energy can be reduced by removing solute atoms from the bulk and segregating them at lattice defects. Here we show how this principle can be utilised through appropriate heat treatments not only to enrich lattice defects by solute atoms, but also to further change these decorated regions into confined ordered structural states or even to trigger localized decomposition and phase transformations. This principle, which is based on the interplay between the structure and mechanics of lattice defects on the one hand and the chemistry of the alloy's solute components on the other hand, is referred to as segregation engineering. In this concept solute decoration to specific microstructural traps, viz. lattice defects, is not taken as an undesired effect, but instead seen as a tool for manipulating specific lattice defect structures, compositions and properties that lead to beneficial material behavior. Owing to the fairly well established underlying thermodynamic and kinetic principles, such local decoration and transformation effects can be tuned to proceed in a self-organised manner by adjusting (i) the heat treatment temperatures for matching the desired trapping, transformation or reversion regimes, and (ii) the corresponding timescales for sufficient solute diffusion to the targeted defects. Here we show how this segregation engineering principle can be applied to design selforganized nano-and microstructures in complex steels for improving their mechanical properties.

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Section: Introduction To the Segregation Engineering Principlementioning

confidence: 99%

Section: Introduction To the Segregation Engineering Principlementioning

confidence: 99%

See 2 more Smart Citations

1 billion tons of nanostructure – segregation engineering enables confined transformation effects at lattice defects in steels

Raabe

Ponge

Wang

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The influence of the microstructure was analyzed by comparing the mechanical parameters derived from the tensile test for all variations [3]. Since the introduction of this method, it has been successfully applied in various fields of new alloys design as in the field of ultrahigh-strength steels for automotive lightweight construction [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Investigation of metallic adapter sleeves for high throughput dilatometry on spherical micro samples

Cramer

Saddei

Surm

et al. 2018

Materialwissenschaft Werkst

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The rods of an available quenching dilatometer are modified for investigations on spherical micro samples (Ø = 1 mm) via metallic adapter sleeves. The experiments can be seen as preliminary tests for a planned high throughput dilatometer, in which adapters are needed as well. Sleeve geometry and materials are varied in the trials to reproduce the transformation of the micro samples using standardized temperature measuring techniques. Sleeves made out of molybdenum produce the best results because molybdenum has a low and nearly constant thermal expansion up to 700 8C. Sleeves of nickel alloy 36 (Invar) or of an austenitic steel (1.4841) do not produce satisfying results. Thermally induced phase transformations of balls of 100Cr6 and X46Cr13 are successfully measured with the existing dilatometer for common macro samples. First the martensitic transformation is investigated, later the process is verified by the isothermal bainitic transformation of 100Cr6.Keywords: Micro sample / dilatometer / initiative "Farbige Zustä nde" / adapter sleeve / phase transformation Mit Hilfe metallischer Adapterhü lsen wird das Gestä nge eines vorhandenen Abschreckdilatometers fü r die Untersuchung sphä rischer Mikroproben (Ø = 1 mm) modifiziert. Die Versuche dienen als Vorversuche fü r ein spä teres Hochdurchsatzverfahren. Stempelgeometrie und -werkstoff werden in den Versuchen variiert, um mit standardisierter Messtechnik, das Umwandlungsverhalten der Mikroproben abzubilden. Hierin erzielen Stempel aus Molybdä n aufgrund der geringen, sowie konstanten thermischen Ausdehnung in einem Temperaturbereich bis 700 8C die besten Ergebnisse. Fe-36Ni (Invar) und der austenitische Stahl 1.4841 eignen sich weniger. Es gelingt, die thermisch induzierte martensitische Phasenumwandlung von Kugeln aus 100Cr6 und X46Cr13 mit einem vorhandenen Makroprobendilatometer aufzunehmen. Durch die zusä tzliche Aufzeichnung der bainitischen Umwandlung des 100Cr6 kann das Verfahren an einer isothermen Transformation mit lä ngerer Haltedauer verifiziert werden.Schlü sselwö rter: Mikroprobe / Dilatometer / Initiative "Farbige Zustä nde" / Adapterhü lse / Phasenumwandlung

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Combinatorial Alloy Design by Laser Additive Manufacturing

Knoll

Ocylok

Weisheit

et al. 2016

steel research int.

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The authors uses laser additive manufacturing (LAM) as a combinatorial method for synthesizing microstructurally and compositionally piecewise graded bulk alloys. Authors fabricate blocks consisting of a sequence of %500 mm thick tool steel layers, each with different chemical composition, by laser metal deposition where alloy powders are deposited layer-wise on a substrate. The reference materials are a Cr-Mo-V hot working tool steel and a Ni-based maraging steel. The layers between them consist of corresponding blends of the two materials with varying composition from layer to layer (alloy volume fractions 80:20, 60:40, 40:60, and 20:80). The bulk alloy is hot rolled and heat treated. Subsequently each layer is characterized for microstructure, chemical composition and mechanical properties using electron back scatter diffraction, tensile testing, and indentation. The approach is an efficient high-throughput method enabling rapid probing of novel compositional alloy blends. It can be applied for finding new alloys both, by LAM and for LAM. For the tool steel blends synthesized here, authors observe that the Cr-Mo-V tool steel, when mixed with the Ni-base maraging steel, can be continuously tuned for a strength-ductility profile in the range of 800-1650 MPa strength and 15-25% tensile elongation.

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Combinatorial design of transitory constitution steels: Coupling high strength with inherent formability and weldability through sequenced austenite stability

Cited by 26 publications

References 25 publications

1 billion tons of nanostructure – segregation engineering enables confined transformation effects at lattice defects in steels

1 billion tons of nanostructure – segregation engineering enables confined transformation effects at lattice defects in steels

Investigation of metallic adapter sleeves for high throughput dilatometry on spherical micro samples

Combinatorial Alloy Design by Laser Additive Manufacturing

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