Structure formation in sintering iron-boron carbide powder composite

Turov, Yu. V.; Khusid, Boris; Voroshnin, L. G.; Хина, Б. Б.; Kozlovskii, I. L.

doi:10.1007/bf00795069

Cited by 13 publications

(4 citation statements)

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“…B 4 C particles break down below 1100 • C, and the iron boride phases form at the interface between B 4 C and iron. Depending on the duration and temperature of the sintering process, the boron content, and the particle size, a single phase (Fe 2 B) or two intermetallic phases (Fe 2 B, FeB) are formed by the diffusion of boron atoms into the iron based materials [20][21][22]. The solubility of boron in steel is higher than 0.004 percent at 1000 • C, and the rate of diffusion is about the same as that of carbon [28].…”

Section: Microstructure Observationsmentioning

confidence: 99%

“…The iron-rich liquid phase is formed between the ceramic particles, and the FeB phase is formed after solidification [19]. At sintering temperatures up to 1100 • C, the Fe 2 B and FeB phases begin to form around boron carbide due to the reaction between iron and boron, resulting in an almost complete breakdown of the B 4 C particles and the formation of graphite inside a porous and borided zone [16,20]. Increasing the sintering temperature (1000-1100 • C) leads to the formation of the liquid phase, and the sintering process is accelerated [20].…”

Section: Introductionmentioning

confidence: 99%

“…At sintering temperatures up to 1100 • C, the Fe 2 B and FeB phases begin to form around boron carbide due to the reaction between iron and boron, resulting in an almost complete breakdown of the B 4 C particles and the formation of graphite inside a porous and borided zone [16,20]. Increasing the sintering temperature (1000-1100 • C) leads to the formation of the liquid phase, and the sintering process is accelerated [20]. Regarding the solid-state sintering, only solid phases are present at the sintering temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Larger B 4 C particles remained in residual form in the structure.In powder metallurgy, solid state diffusion plays a major role in the formation and growth of interfacial bonding, formed by the dissolution or reaction of the B 4 C particles and the iron matrix.B 4 C particles break down below 1100 • C, and the iron boride phases form at the interface between B 4 C and iron. Depending on the duration and temperature of the sintering process, the boron content, and the particle size, a single phase (Fe 2 B) or two intermetallic phases (Fe 2 B, FeB) are formed by the diffusion of boron atoms into the iron based materials[20][21][22]. The solubility of boron in steel is higher than 0.004 percent at 1000 • C, and the rate of diffusion is about the same as that of carbon[28].…”

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Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

Nair

Hamamcı

2020

Metals

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The objective of this study is to investigate the impact behavior of iron-based composites reinforced with boron carbide (B4C) particles and in-situ synthesized iron borides (Fe2B/FeB). The composite specimens (Fe/B4C) were fabricated by hot-pressing under a pressure of 250 MPa at 500 °C, and sintered at a temperature of 1000 °C. The effects of the reinforcement ratio on the formation of in-situ borides and impact behavior were investigated by means of different volume fractions of B4C inside the iron matrix: 0% (un-reinforced), 5%, 10%, 20%, and 30%. Drop-weight impact tests were performed by an instrumented Charpy impactor on reinforced and un-reinforced test specimens. The results of the impact tests were supported with microstructural and fractographical analysis. As a result of in-situ reactions between the Fe matrix and B4C particles, Fe2B phases were formed in the iron matrix. The iron borides, formed in the iron matrix during sintering, heavily affected the hardness and the morphology of the fractured surface. Due to the high amount of B4C (over 10%), porosity played a major role in decreasing the contact forces and fracture energy. The results showed that the in-situ synthesized iron boride phases affect the impact properties of the Fe/B4C composites.

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Section: Microstructure Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

Nair

Hamamcı

2020

Metals

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Thermal synthesis of Fe–B4C powder master alloys

Baglyuk

Napara-Volgina

Vol’fman

et al. 2009

Powder Metall Met Ceram

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The paper examines the thermal synthesis of master alloys from a mixture of iron and boron carbide powders. It is shown that the content of boron decreases as compared with the starting mixture and the boron/carbon ratio in the master alloy powder changes with increasing synthesis temperature. Thus the initial content of boron carbide in the mixture insignificantly influences the boron/carbon ratio after sintering. At the same time, the content of boron carbide in the mixture and synthesis temperature essentially influence the structure and phase composition of the master alloy obtained.Iron-based boron-bearing alloys attract researchers' attention as they have high hardness, strength, and wear resistance and are relatively cheap. They can be thus regarded as promising materials for structural wearresistant alloys [1][2][3].Boron carbide is the most effective boron-bearing element for alloying powder steels [4]. At low temperatures (1050-1150°C), it actively interacts with iron to form solid metallic compounds (iron borides and carboborides), which harden the material. The interaction of boron carbide particles with iron when compacts are sintered yet involves secondary porosity, when pores form instead of original B 4 C particles [4].The solubility of boron in iron is very low (up to 0.08% [3]), and the introduction of small additions of boron is challenging since it needs to be uniformly distributed over the charge.Powder materials are much easier doped if master alloys are introduced into the charge instead of elementary powders mixed; in addition, such sintered materials usually have higher strength and plasticity [5]. The secondary porosity should obviously be prevented in using boron-bearing master alloys.The production and use of boron-bearing powder master alloys have hardly been examined. The objective of this paper is to examine the synthesis, chemical and phase compositions, and structural state of Fe-B 4 C master alloys with high content of boron carbide.Master alloys with different compositions were produced as follows. Iron powders of PZhRZ.160.28 grade (GOST 9849-86) were mixed with 6-15 wt.% boron carbide (20.7% C and 77.2% B) with particles smaller than 63 μm in a drum mixer for 1 h. The mixtures were pressed under 400 MPa into porous briquettes, which were sintered in a muffle furnace for 1 h at 1050, 1100, and 1200°C in a melt-sealed container. To displace excess air and create reducing media in the container, about 2% paraffin shavings (relative to the mass of the backfill) were added to the backfill (calcined alumina). After thermal synthesis, the samples looked like a porous sponge with typical

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Structure and properties of sintered iron–boron–carbon alloys with different carbon contents

Napara-Volgina

Baglyuk

Orlova

et al. 2011

Powder Metall Met Ceram

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The structure and mechanical and tribotechnical properties of iron-boron-carbon alloys produced from a mixture of iron, boron carbide, and graphite powders by single pressing and sintering are used to examine heterophase wear-resistant materials containing from 0.8 to 2.4% boron and from 0.7 to 1.6% fixed carbon. The wear resistance of the materials depends on the ratios of boron and carbon in them and on their total content and substantially exceeds the wear resistance of ShKh15 steel chosen as a reference sample.Iron-carbon alloys are most commonly used structural powder materials since their production is relatively simple and the initial components are readily available [1,2]. To improve basic mechanical and operational properties of these alloys, they must be additionally doped.Boron carbide is a compound that has proved to be highly effective in doping sintered structural iron-based materials (especially in the manufacture of parts subjected to wear during operation) [3-9] and wear-resistant coatings [10][11][12][13][14].We have analyzed papers that focus on the production and properties of boron-containing powder materials for different purposes (including wear-resistant ones) that are made of iron powder mixtures with different contents of boron carbide and revealed that the structure and properties of these materials can be controlled not only through variation in their B 4 C content [7] but also through additional introduction of carbon into the initial charge [8], which leads to significant hardening of Fe-B 4 C materials.There have been no systematic studies of the tribological properties and structure of these materials. The only exception is the paper [5] that provides the wear characteristics of Fe + 3% B 4 C material; however, it is difficult to assess them appropriately as the paper includes no data on experimental conditions, in particular, loading and the counterface rotation speed and time.

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Structure formation in sintering iron-boron carbide powder composite

Cited by 13 publications

References 1 publication

Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

Thermal synthesis of Fe–B4C powder master alloys

Structure and properties of sintered iron–boron–carbon alloys with different carbon contents

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