Influence of spark plasma sintering parameters on densification and mechanical properties of boron carbide

The densification behavior of boron carbide without sintering additives is reported for temperatures in the range of 1100 °C to 1800 °C by spark plasma sintering (SPS) technique together with the sintering parameters (Holding Time and Pulsed DC). The influence of porosity on mechanical properties (hardness, fracture toughness and elastic modulus) of boron carbide prepared by SPS is measured. Pulsed DC current is found to play a dominant role in the densification of boron carbide and in achieving near theoretical density at lower sintering temperature compared to conventional sintering techniques. Hardness, fracture toughness and elastic modulus of fully dense B4C are measured as 37.2 GPa, 2.8 MPa.m1/2 and 570 GPa respectively. Microstructural analysis indicates the presence of deformation twins in boron carbide grains.