Effect of Al addition on pressureless sintering of B4C

Mashhadi, Mehri; Taheri-Nassaj, E.; Sglavo, Vincenzo M.; Sarpoolaky, H.; Ehsani, N.

doi:10.1016/j.ceramint.2008.03.003

Cited by 81 publications

(36 citation statements)

References 21 publications

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“…The infiltrated composites consisted of four phases based on the XRD results shown in Fig. 1, including the original B 13 C 2 particles, ternary B 12 (C,Si,B) 3 compounds formed as a product of B 13 C 2 and Si reaction, SiC, and residual Si.…”

Section: (1) Phase Compositionmentioning

confidence: 99%

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

Zhang

Wang

et al. 2014

J. Am. Ceram. Soc.

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The present paper is concerned on the effect of infiltration temperature on the components, microstructure, and mechanical properties of reaction-bonded boron carbide (RBBC) ceramics. RBBC ceramics were fabricated by reactive infiltration of molten silicon (Si) into porous preforms containing boron carbide (B 4 C) and free carbon. It has been found that infiltration temperatures have significant influence on the infiltration reactions involved and therefore the evolution of different phases formed in the RBBC ceramics. An increase in grain size of boron carbide particles through the coalescence of neighboring grains was observed at certain infiltration temperatures. The morphology of silicon carbide (SiC) phases developed from discontinuous and cloud-like SiC to continuous and integrated SiC zones with the increase of infiltration temperatures. With increasing temperatures up to 1600°C, the hardness, flexural strength, and fracture toughness all increased. When the temperatures exceeded 1600°C, while the hardness and flexural strength decreased, the fracture toughness continued to increase.

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Section: (1) Phase Compositionmentioning

confidence: 99%

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

Zhang

Wang

et al. 2014

J. Am. Ceram. Soc.

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“…Molten aluminum reacts with boron carbide easily, thus infiltration process may be achieved. Resulted B 4 CSiC-Al 2 O 3 -Al composites exhibit combination of high hardness and high toughness without defeating the aim of obtaining lightweight structure [7]. It is very hard to obtain 100% dense B 4 C-SiC-Al 2 O 3 composites due to presence of strong covalent bonds, high resistance to grain boundary sliding and absence of plasticity which limit their diffusion coefficients in sintering process.…”

Section: Introductionmentioning

confidence: 99%

“…It is very hard to obtain 100% dense B 4 C-SiC-Al 2 O 3 composites due to presence of strong covalent bonds, high resistance to grain boundary sliding and absence of plasticity which limit their diffusion coefficients in sintering process. Combination of high temperatures and high pressures used in sintering process is the most important economic problem besides the high cost of powders [7]. Compared with traditional sintering techniques, melt infiltration is a promising process to produce composite with porous ceramic preforms due to its several advantages.…”

Section: Introductionmentioning

confidence: 99%

Melt Infiltration Casting of Alumina Silicon Carbide and Boron Carbide Reinforced Aluminum Matrix Composites

Kalkanlı¹,

Durmaz²,

Kalemtaş³

et al. 2017

J Material Sci Eng

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This paper discuss the effect of processing details such as particle size, sintering temperature, preform preparation, aluminum alloy characteristics and melt temperature on the final mechanical properties of ceramic phase reinforced metal matrix composites. Since alloy composition was determined as 7075 and 7085 optimum solutionizing and ageing temperatures were studied to determine maximum hardness values. For only 7085 alloy best solutionizing temperature is 465°C and for 7075 alloy the maximum hardness achived as 178 BHN after heat treatment at 475°C. Alloys were heat treated for recystallization after hot rolling grain size were measured as 100-120 µm for 7085 alloy matrix.Various sintering temperatures were used for preform preparation such as 1300-1450°C. In 85% Al 2 O 3 reinforced 7085 Alloy based MMCs preforms sintered at 1450°C high hardness values were achieved as 545 BHN. Intermetallic phase was determined in 7075 and 7085 alloys selected as alloy matrix. Al 2 Cu intermetallic pecipitate (θ phase) was determined as dominant second phase after T6 heat treatment but highly expected phase in 7000 series alloys MgZn 2 (η phase) was not determined by XRD and SEM analysis techniques due to ultrafine precipitate size and homogeneous distribution.

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“…The zoned domains in the crystalline grains of the B 4 C solid solution increase the difficulties of identification of diffraction pattern by automatic procedures as in electron backscatter diffraction (EBSD) results of B 4 C which in the presence of Al as in the AA1100 -16 vol% B 4 C composite tend to be misidentified with the Al phase itself [11]. Disadvantages of the B 4 C ceramics are the low self-diffusion coefficient, limiting densification by sintering and also brittleness, both being due to the covalent bonding of B 4 C. Several methods were developed to prepare B 4 C ceramics such as hot pressing [12][13] and pressureless sintering [14][15], however the extremely high temperatures needed of 2000 -2200 ºC increase the global cost and make the materials less attractive. A way to overturn such inherent problems to produce useful materials based on B 4 C is by using a different approach such as the infiltration method with a metal as infiltrate forming composites [1,[16][17].…”

Section: Introductionmentioning

confidence: 99%

Study of multi-carbide B₄C-SiC/(Al, Si) reaction infiltrated composites by SEM with EBSD

Almeida

Ferro

Ravanan

et al. 2014

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

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Abstract. In the definition of conceptual developments and design of new materials with singular or unique properties, characterisation takes a key role in clarifying the relationships of composition, properties and processing that define the new material. B 4 C has a rare combination of properties that makes it suitable for a wide range of applications in engineering: high refractoriness, thermal stability, high hardness and abrasion resistance coupled to low density. However, the low self-diffusion coefficient of B 4 C limits full densification by sintering. A way to overturn this constraint is by using an alloy, for example Al-Si, forming composites with B 4 C. Multi-carbide B 4 C-SiC/(Al, Si) composites were produced by the reactive melt infiltration technique at 1200 -1350 ºC with up to 1 hour of isothermal temperature holds. Pressed preforms made from C-containing B 4 C were spontaneously infiltrated with Al-Si alloys of composition varying from 25 to 50 wt% Si. The present study involves the characterisation of the microstructure and crystalline phases in the alloys and in the composites by X-ray diffraction and SEM/EDS with EBSD. Electron backscatter diffraction is used in detail to look for segregation and spatial distribution of Si and Al containing phases during solidification of the metallic infiltrate inside the channels of the ceramic matrix when the composite cools down to the eutectic temperature (577 ºC). It complements elemental maps of the SEM/EDS. The production of a flat surface by polishing is intrinsically difficult and the problems inherent to the preparation of EBSD qualified finishing in polished samples of such type of composites are further discussed.

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Effect of Al addition on pressureless sintering of B4C

Cited by 81 publications

References 21 publications

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

Melt Infiltration Casting of Alumina Silicon Carbide and Boron Carbide Reinforced Aluminum Matrix Composites

Study of multi-carbide B₄C-SiC/(Al, Si) reaction infiltrated composites by SEM with EBSD

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Effect of Al addition on pressureless sintering of B4C

Cited by 81 publications

References 21 publications

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

The Role of Infiltration Temperature in the Reaction Bonding of Boron Carbide by Silicon Infiltration

Melt Infiltration Casting of Alumina Silicon Carbide and Boron Carbide Reinforced Aluminum Matrix Composites

Study of multi-carbide B4C-SiC/(Al, Si) reaction infiltrated composites by SEM with EBSD

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Study of multi-carbide B₄C-SiC/(Al, Si) reaction infiltrated composites by SEM with EBSD