Thermal and Mechanical Properties of B4C-ZrB2 Ceramic Composite

Abstract

B 4 C and B 4 C-ZrB 2 (Zr-3-5 wt.%) ceramic materials were obtained by the method of hot pressing at temperature range 2,050-2,140 °C and 34-40 MPa pressure, and subject to further thermal treatment at 1,800 °C. Physical and mechanical properties of the above composite, the effect of ZrB 2 on the process parameters of items formation and on the obtained composite features were studied. Relatively perfect microstructure and optimum physical and mechanical properties are characteristic for B 4 C-3.7% ZrB 2 ceramics, the relative density of which equals 100%. Compared to B 4 C, it demonstrated 10% reduced average grain size and 8% higher fracture toughness; Reduced linear thermal expansion coefficient and mechanical bending strength and doubled thermal conductivity at high temperatures; Increased Young modulus, hardness and compressive strength, which make 363 MPa; 30.1 GPa and 3,175 MPa, respectively. When alloying phase (ZrB 2) content increased to 6.2 wt.%, average grain size growth to 8 μm, fracture toughness, microhardness and mechanical bending strength decreased and made approximately 2.37 MPa√m, 28.2 GPa and 292 MPa, respectively.

Development of the method of production of the ultrafine macrohomogeneous composite powder

“…From the obtained results, it is obvious that in the result of the use of ultrafine zirconium dioxide, density parameter improved by 3-4%. Such an effect was not observed in work [2], where zirconium oxide powder with particle sizes 2-3 μm was used as the source of zirconium.…”

“…Doping boron carbide with components, inserting a portion of free electrons is one of the ways to decrease the above brittleness. Some published works describe boron carbide doping with transition metals of groups IV-VI of the Periodic Table to improve its crack resistance [1][2][3].…”

“…Boron carbide occupies a special place among the reactor materials, which is explained by its unique nuclear properties [1]. It contains both stable isotope 10 V with high thermal and fast neutron absorption cross-section, and carbon and 11 V isotope nuclei, which effectively moderate fast neutrons [1,2].…”

“…Zirconium dioxide nano-sized powder, formed during grinding initial boron carbide, in the result of attrition of the grinding elements, which are less hard, compared to the grinded material, gets homogeneously distributed in the system [12]. The hardness of initial B 4 C makes Hv(B 4 C) = 28-40 GPa, while the hardness of grinding elements makes Hv(ZrO 2 ) = 13-15 GPa [2].…”

Advanced Boron Carbide Matrix Nanocomposites Obtained from Liquid-Charge: Focused Review

“…Detailed results of boron carbide matrix nanocomposites obtained using the liquidcharge technology are published in research papers [1][2][3][4][5][6][7][8][9][10][11][12], conference reports [13,14], and reviews [15][16][17][18][19][20][21][22].…”