Enhancement of hardness, modulus and fracture toughness of the tetragonal (Fe,Cr)2B and orthorhombic (Cr,Fe)2B phases with addition of Cr

Lentz, Jonathan; Röttger, Arne; Großwendt, Felix; Theisen, W.

doi:10.1016/j.matdes.2018.06.040

Cited by 46 publications

(20 citation statements)

References 70 publications

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“…Recent investigations of the micromechanical properties of the M 2 B‐type boride show that both microhardness and microfracture toughness of the M 2 B boride are superior to the Cr‐rich M 7 C 3 carbide. The reported values extend to hardness and toughness values that are otherwise only known to MC monocarbides …”

Section: Introduction and Objectivesupporting

confidence: 57%

“…as well as the orth. M 2 B phase as a function of its chemical composition (provided in literature) shows that with increasing the Cr content of the M 2 B phase, both hardness and fracture toughness of the M 2 B phase can be enhanced, simultaneously. The tetr.…”

Section: Resultsmentioning

confidence: 99%

“…Hardness and toughness of the orth. M 2 B phase monotonously increase with an increase in Cr content from 22 MPa and 2 MPam 1/2 at 25 at% Cr (corresponding to 33 mass% Cr) to 27 MPa and 3.3 MPam 1/2 at 57 at% Cr (corresponding to 77 mass% Cr) …”

Section: Resultsmentioning

confidence: 99%

“…The tetr. M 2 B phase possesses an optimum of hardness and toughness (22 GPa and 3.5 MPam 1/2 ) at 4–5 at% Cr (corresponding to 5–6 mass% Cr) . Hardness and toughness of the orth.…”

Section: Resultsmentioning

confidence: 99%

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Microstructures, Heat Treatment, and Properties of Boron‐Alloyed Tool Steels

Lentz

Röttger

Theisen

2019

steel research int.

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To enable the development of novel Fe-C-B-Cr and Fe-C-B-Cr-Mo cold work tool steels, the microstructures and hardness-tempering behaviors of hypoeutectic laboratory melts are investigated. The results show that increasing Cr content enhances the thermodynamic stability of the ultrahard M 2 B borides. The formation of carboborides is suppressed by adjusting the B/(C þ B) ratio, Cr content, and austenitization temperature. A secondary hardenability at 500 C is achieved by Mo addition. In addition, Mo stabilizes the M 23 (C,B) 6 phase and at higher contents the M 3 B 2 boride. Based on these investigations, Fe0.4C1B-Cr alloys are designed which, inspired by the microstructure of the steel X153CrMoV12-1, feature a α 0 -Fe hardenable matrix but 15 vol% of eutectic M 2 B borides instead of M 7 C 3 for wear protection. The Fe0.4C1B-Cr steels are produced by casting and hot rolling as well as powder metallurgy and hot isostatic pressing. The (tribo-) mechanical properties are investigated and compared with X153CrMoV12-1. Fracture toughness, bending strength, wear resistance, and hardness of the novel Fe0.4C1B-Cr alloys are found to be similar or superior to the steel X153CrMoV12-1, at decreased material cost.

show abstract

Section: Introduction and Objectivesupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…The tetr. M 2 B phase possesses an optimum of hardness and toughness (22 GPa and 3.5 MPam 1/2 ) at 4–5 at% Cr (corresponding to 5–6 mass% Cr) . Hardness and toughness of the orth.…”

Section: Resultsmentioning

confidence: 99%

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Microstructures, Heat Treatment, and Properties of Boron‐Alloyed Tool Steels

Lentz

Röttger

Theisen

2019

steel research int.

Self Cite

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“…Alloying is a direct and effective means to improve the properties of alloys [27]. In order to improve the toughness of HBCS, Cr, W, Cu, Ni, and other elements have been widely investigated [21,[28][29][30][31][32][33][34][35]. Ma [21] and Lentz [28] et al pointed out that with an increase of Cr, the morphology of Fe 2 B changes from a blocky shape to a rod-like shape.…”

Section: Introductionmentioning

confidence: 99%

Effect of Mo Concentration on the Microstructure Evolution and Properties of High Boron Cast Steel

et al. 2020

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The microstructure evolution, mechanical properties, and tribological properties of high boron cast steel (HBCS) with various Mo concentrations are investigated. The results indicate that Mo addition can significantly modify the microstructure and enhance the comprehensive properties. With the increase of Mo concentration, borides change from the original fish-bone Fe-rich and Cr-rich M2B to dendritic Fe-rich M2B, blocky and cluster-like Cr-rich M2B, and grainy Mo-rich M2B. The hardness of HBCS increases gradually with the increase of Mo content due to the solid solution strengthening and the refinement of M2B. It can be found that all the samples exhibit quasi-cleavage, but the impact toughness increases firstly and reaches the maximum value when the concentration of Mo is 2.10 wt.%, which is the result of the dispersive distribution of M2B rather than the original fish-bone M2B. Subsequently, the impact toughness begins to decrease as the concentration of Mo further increases because of the extensive formation of grainy Mo-rich M2B at the grain boundary. Meanwhile, the wear results reveal that the average friction coefficient and wear ratio decrease with the increase of Mo content, and the wear mechanism changes from abrasive wear and adhesive wear to abrasive wear when the concentration of Mo exceeds 2.10 wt.%.

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Mechanical Properties of an Ultrahard In Situ Amorphous Steel Matrix Composite

Yazdani,

Dewitt,

Huang

et al. 2024

Adv Eng Mater

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We report compression tests on micro‐pillars manufactured from bulk specimens of partially devitrified SAM2×5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4). Yield strength values of ∽6 GPa were obtained. Such a high strength can be attributed to the higher glass transition temperature (883 K) of this material, which impedes the multiplication of shear bands under loading, and to the presence of hard crystalline domains that result from devitrification of the amorphous powders during powder consolidation. The Vickers hardness of the specimens was found to be strongly correlated to the processing temperature and, hence to the volume of crystalline phases present in the specimens. As the processing temperature is increased, there is a reduction in free volume from the structural relaxation process in the amorphous alloy, leading to the eventual nucleation of crystalline phases of BCC Fe, Cr2B, Cr21.30Fe1.7C6, or Fe23B2C4, during the densification process. These results shed light on the relationship between nanocrystalline domains and the mechanical behavior of Fe‐based amorphous/crystalline composites.This article is protected by copyright. All rights reserved.

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Enhancement of hardness, modulus and fracture toughness of the tetragonal (Fe,Cr)2B and orthorhombic (Cr,Fe)2B phases with addition of Cr

Cited by 46 publications

References 70 publications

Microstructures, Heat Treatment, and Properties of Boron‐Alloyed Tool Steels

Microstructures, Heat Treatment, and Properties of Boron‐Alloyed Tool Steels

Effect of Mo Concentration on the Microstructure Evolution and Properties of High Boron Cast Steel

Mechanical Properties of an Ultrahard In Situ Amorphous Steel Matrix Composite

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