Mechanical and thermal properties of hot pressed B4C-Cr3C2-hBN materials

In the present study, boron carbide matrix composites were manufactured by hot-pressing method. In order to reduce the boron carbide sintering temperature and to improve the mechanical properties, such as bending strength, critical stress intensity factor and hardness, chromium carbide, because of its low melting point and high thermal expansion coefficient, was added in various volume quantities. In order to prepare the material for cutting tool or ceramics sealing applications hexagonal boron nitride in quantities ranging from 2 and 8 vol.% was added to reduce the friction coefficient. The sinters were subjected to the abrasive test and to elastic properties examinations. Computer simulations of thermal stresses were prepared. The measured mechanical properties were supported by phase analysis and microstructural observations. Because the carrying out of heat is very important for mechanical properties of materials the influence of additives on thermal conductivity was also presented.