Solidification and phase formation of alloys in the hypoeutectic region of the Fe–C–B system

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

doi:10.1016/j.actamat.2015.07.037

Cited by 54 publications

(31 citation statements)

References 28 publications

(39 reference statements)

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“…Thus, it can be confirmed that the net-like phase is Fe2B, the rod-like and block-like structures are composed of CrFeB and Cr2B phases (see Figure 3c). Such hard borides have been widely reported in the literature [24,44,45]. Figure 4b, it can be seen that the size of the block-like particles is much larger than that in the BCr-15 sample, and such large particles are mainly distributed at the grain boundaries.…”

Section: Phase Evolutionsupporting

confidence: 50%

Evolution of the Microstructure and Properties of Pre-Boronized Coatings During Pack-Cementation Chromizing

Zeng

Yang

et al. 2020

Coatings

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The effect of chromizing time on the microstructure and properties of B-Cr duplex-alloyed coating prepared by a two-step pack-cementation process was investigated. The phases, microstructure, and element distribution of three coatings obtained were characterized by X-ray diffraction (XRD), secondary electron imaging (SEI), backscattering electron imaging (BSEI), and energy dispersive spectroscopy (EDS), respectively. The results show that as the chromizing time increases, the net-like Fe2B and rod-like CrFeB phases in the coating gradually disappear, and finally completely transform into the block-like Cr2B and CrxCy (Cr7C3 and Cr23C6) phases. The growth kinetics analysis shows that interface reaction dominates the coating growth during the early stage of chromizing, while atomic diffusion gradually controls the coating growth at the later stage. The evolution mechanism of the B-Cr duplex-alloyed coating was also discussed.

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Section: Phase Evolutionsupporting

confidence: 50%

Evolution of the Microstructure and Properties of Pre-Boronized Coatings During Pack-Cementation Chromizing

Zeng

Yang

et al. 2020

Coatings

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“…Commonly, the active boron atoms dissolved into matrix are able to stabilize undercooled austenite [46] and improve the hardenability of steel [21,22,44] resistance and hardness contributed by boron have been reported [22]. The harder boro-carbides may partially contribute to the red hardness increasing with LaB 6 content.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…It means the non-equilibrium segregation of boron along vacancy sinks (i.e. grain boundaries), which commonly occurs in boron containing steels during cooling [18,21,44], are not detected in the as-tempered DFT 10LB. Similarly, Keown [45] also stated that no boron segregation occurs in Cr-Mo-V creep-resisting steel after tempered at 700℃, though Karlsson [18] demonstrated that boron atoms are very mobile and segregate even after cooled from below 500℃.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Direct fabrication of high-performance high speed steel products enhanced by LaB 6

et al. 2016

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A direct fabrication technology (DFT) without smelting has been developed for fabricating sophisticated high speed steel products with low pollution, near-net shaping and short process. The steel consisting of (wt. %): 6.4W, 5.0Mo, 4.2Cr, 3.1V, 8.5Co and 1.28C, was fabricated as exemplary material. The activated and reactive sintering of green compacts under vacuum with low activation energy, redox reaction enhanced diffusion and the construction of concentration gradient of alloying elements around pores, promotes the nearly full densification (>99.40%). Also, the DFT steels show high purity and superior mechanical properties. Minor strengthening agent LaB 6 (0.1 wt. %), which is easily to be accurately introduced in DFT, obviously increases the hot hardness, temper resistance, bend strength and toughness of DFT M3:2. The strengthening effect of boron atoms and La-rich complexes are proposed to directly result in the high hot hardness and temper resistance of LaB 6 containing steel.

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“…In the ternary system Fe–C–B, the tetr. M 2 B boride as well as the carboborides M 3 (C,B) and M 23 (C,B) 6 is found to be stable based on C/B ratio and temperature . In literature, the micromechanical properties of these phases are found to differ significantly: the higher the metal‐to‐metalloid ratio, the higher the proportion of metallic‐bonding character in relation to covalent bonding and thus lower the hardness .…”

Section: Resultsmentioning

confidence: 99%

“…On this account, the objective of alloy developments of novel CWS3 is to stabilize the hardest boride of Fe 2 B type inside a martensitic steel matrix. However, regarding ternary Fe–C–B alloys, studies have shown that C contents, which are required for martensitic hardening, simultaneously stabilize high amounts of the softer and thus unwanted carboborides of type Fe 3 (C,B) and/or Fe 23 (C,B) 6 . Consequently, ternary Fe–C–B alloys are not suitable for the design of high‐grade CWS3 and additions of further alloying elements are needed to stabilize the M 2 B boride …”

Section: Resultsmentioning

confidence: 99%

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.

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Solidification and phase formation of alloys in the hypoeutectic region of the Fe–C–B system

Cited by 54 publications

References 28 publications

Evolution of the Microstructure and Properties of Pre-Boronized Coatings During Pack-Cementation Chromizing

Evolution of the Microstructure and Properties of Pre-Boronized Coatings During Pack-Cementation Chromizing

Direct fabrication of high-performance high speed steel products enhanced by LaB 6

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

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