Mechanical behaviour at high temperature of spark plasma sintered boron carbide ceramics

Belon, Rémy; Antou, Guy; Pradeilles, Nicolas; Maı̂tre, Alexandre; Gosset, Dominique

doi:10.1016/j.ceramint.2017.02.053

Cited by 40 publications

(24 citation statements)

References 23 publications

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“…Both powders have been sintered without additives using a SPS apparatus (Fuji‐Syntex, Dr Sinter 825, Japan). The applied sintering conditions have been carefully described in a previous work . The density of monoliths was determined using the Archimedes method in ethanol.…”

Section: Methodsmentioning

confidence: 99%

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Influence of chemical composition on mechanical properties of spark plasma sintered boron carbide monoliths

et al. 2018

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Fully dense boron carbide monoliths exhibiting fine microstructure (i.e., submicrometric grain size) are sintered by Spark Plasma Sintering. Two different commercial powder batches, exhibiting different stoichiometries (i.e., B/C ratio and oxygen content) and various amounts of secondary phases (i.e., boric acid and free carbon), are used. Their chemical composition is well‐defined by coupling different methods (Transmission Electron Microscopy associated with XRD analyses, and Instrumental Gas Analysis), and are correlated with their mechanical properties, characterized from meso‐ to macro‐scopic scales by nano‐indentation and ultrasonic pulse echography. The presence of secondary phases (graphite and boric acid) is evidenced in various proportions in each powder batch. If the boric acid disappears during sintering, the graphite remains. However, for the considered amounts of graphite (lower than 1 wt%), the low variations in graphite content have no significant effect on hardness and elasticity values. At the opposite, the presence of oxygen in boron carbide lattice, leading to a boron oxycarbide phase, induces a decrease in both hardness and elasticity properties.

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Section: Methodsmentioning

confidence: 99%

“…The applied sintering conditions have been carefully described in a previous work. 8 The density of monoliths was determined using the Archimedes method in ethanol. The measured density by helium pycnometry (AccuPyc II 1340, Micromeritics) on the powders was used as a reference in order to calculate the relative density of the sintered pellets.…”

Section: Methodsmentioning

confidence: 99%

Influence of chemical composition on mechanical properties of spark plasma sintered boron carbide monoliths

et al. 2018

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“…When looking at Figure 6-right, a sharp slope discontinuity appears on the evolution of the thickness of the sample (after soft polishing to remove possible oxidation) at about 1600°C. This temperature corresponds to the admitted brittle to ductile temperature threshold (BDTT) of boron carbide [19]. Here, crossing this transition could allow a relaxation of the helium pressure in the bubbles, this leading to a significant swelling of the sample: such a consideration should be taken into account when looking at safety issues.…”

Section: Annealingmentioning

confidence: 99%

Evolution of thermo-physical properties and annealing of fast neutron irradiated boron carbide

Gosset

Kryger²,

Bonal

et al. 2018

Journal of Nuclear Materials

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Boron carbide is widely used as a neutron absorber in most nuclear reactors, in particular in fast neutron ones. The irradiation leads to a large helium production (up to 10 22 /cm 3) together with a strong decrease of the thermal conductivity. In this paper, we have performed thermal diffusivity measurements and X-ray diffraction analyses on boron carbide samples coming from control rods of the French Phenix LMFBR reactor. The burnups range from 10 21 to 8.10 21 /cm 3. We first confirm the strong decrease of the thermal conductivity at the low burnup, together with high microstructural modifications: swelling, large microstrains, high defects density, and disordered-like material conductivity. We observe the microstructural parameters are highly anisotropic, with high micro-strains and flattened coherent diffracting domains along the (00l) direction of the hexagonal structure. Performing heat treatments up to high temperature (2200°C) allows us to observe the material thermal conductivity and microstructure restoration. It then appears the thermal conductivity healing is correlated to the micro-strain relaxation. We then assume the defects responsible for most of the damage are the helium bubbles and the associated stress fields.

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“…Boron carbide (B 4 C) based ceramic materials have good potential for various industrial fields due to their extraordinary physical and mechanical properties. B 4 C possesses mainly an exceptional hardness of 20-45 GPa and high Young's modulus of 360-500 GPa [1][2][3]. It has high melting point of 2450°C and low density of 2.52 g/cm 3 [2,[4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…However, the main disadvantages of B 4 C based ceramics are their relatively low fracture toughness and poor sinterability [2,7,[9][10][11]. Depending on the consolidation method and process parameters the fracture toughness of monolithic B 4 C reaches values of 1.2-4.5 MPa•m 1/2 [1,2,[7][8][9][10][11][12][13][14]. As these values are insufficient for many industrial applications, the fracture toughness of B 4 C is a critical property and should be enhanced [6,11].…”

Section: Introductionmentioning

confidence: 99%

Reactive sintering of B4c-TiB2 composites from B4 and TiO2 precursors

Švec

Gábrišová

Brusilová

2020

PAC

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The effect of sintering temperature in the interval from 1775 to 1850?C on the density, microstructure, hardness and fracture toughness of ceramic composites consisting of a boron carbide matrix and titanium diboride secondary phase was studied. The composites were hot pressed using in situ reaction between boron carbide and 40 wt.% of titanium dioxide additive. The samples were hot pressed at different temperatures but for the constant time of 60min, under the pressure of 35MPa in vacuum of 10 Pa. Both Vickers hardness and fracture toughness of the composites increased with the sintering temperature.Maximal hardness of 29.8GPa and fracture toughness of 6.9MPa?m1/2 were achieved for the composite with 29.6 vol.% of titanium diboride secondary phase sintered at the highest sintering temperature of 1850?C.

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Mechanical behaviour at high temperature of spark plasma sintered boron carbide ceramics

Cited by 40 publications

References 23 publications

Influence of chemical composition on mechanical properties of spark plasma sintered boron carbide monoliths

Influence of chemical composition on mechanical properties of spark plasma sintered boron carbide monoliths

Evolution of thermo-physical properties and annealing of fast neutron irradiated boron carbide

Reactive sintering of B4c-TiB2 composites from B4 and TiO2 precursors

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