Search

An investigation was carried out into the effect of porosity in the range 2–46% and grain size in the range (5–140)·10−6 m on the mechanical properties of boron carbide. It is shown that the level of mechanical properties of boron carbide produced by hot pressing from powders synthesized from the elements is 1.5 times higher than that of boron carbide produced by other methods. Increasing the porosity of boron carbide to 46% decreases its strength by a factor of six or seven. Increasing the grain size to 140·10−6 m has the same effect. An analysis is made of equations describing the dependence of the mechanical properties of boron carbide on porosity and grain size. The constants of these equations have been determined.

1. A study was made of the densification kinetics of B4C in hot pressing at temperatures in the range 1800–2200°C under a pressure of 225 kgf/cm2. 2. The effects of applied pressure in hot pressing at a temperature of 2100°C were investigated over the range 75–375 kgf/cm2. 3. It is demonstrated that the densification of boron carbide is controlled by a process leading to non-linear creep, whose rate is a function of the square of stress.