Mixed Particle Size Effect on Improvement of Mechanical Properties of Reaction Bonded B4C

The research was aimed for improving the mechanical properties of reaction bonded boron carbide (RBBC) through use of two boron carbide (B4C) powders in the initial preform. Experimental results show that the Young’s modulus, Knoop hardness, and flexural strength of RBBC, produced with the combination of two powders, are greater by ∼15.2%, ∼33.8% and ∼15.5%, respectively, compared to that produced with single, i.e. fine B4C powder. The increase in ceramic phase (B4C and B4C +SiC) and reduction in residual Si content in the RBBC produced with mixed powders lead to an enhancement in its mechanical properties. Both RBBC exhibit indentation size effect and such characteristics are corroborated by their respective brittleness index.