Synthesis and physicomechanical properties of B sub(4)C-VB sub(2) composites

• Published in: Powder metallurgy and metal ceramics Vol. 45; no. 1-2; pp. 47 - 58
• Main Authors: Grigorjev, ON, Kovaljuk, V V, Zaporozhets, OI, Bega, N D, Galanov, BA, Prilutskii, E V, Kotenko, V A, Kutranj, T N, Dordienko, NA
• Format: Journal Article
• Language: English
• Published: 01.01.2006
• Subjects: Bend strength; Borides; Carbon; Ceramics; Concentration (composition); Obstacles; Strength; Vanadium
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-006-0041-x

We have studied the properties of composites in the B sub(4)C-VB sub(2)-C system, obtained by reaction synthesis with hot pressing. We have established that the presence of free carbon and vanadium boride in the ceramic makes it possible to activate the sintering process and to obtain a dense, highly dispersed ceramic with good structural homogeneity parameters for lower isothermal holding temperatures. The composite ceramic has higher hardness and bending strength over a broad range of vanadium boride content than the monophase ceramic based on boron carbide. The strength properties of the composite ceramic containing up to 8 vol.% vanadium boride are improved by means of a mechanism involving propagating cracks bending around obstacles. When the VB sub(2) concentration increases further, the properties of the composite are determined by a microcracking mechanism. In this case, we observe relatively small changes in the elastic characteristics, which depend linearly on the composition of the ceramic. Introducing vanadium boride into the material is also accompanied by an increase in the contact and microstructural strengths. The results obtained indicate that the new composite material is promising for fabricating wear-resistant and shock-resistant components of various structures and machines.