Improving the Material Properties of Boron Carbide Through Elemental Inclusion

Boron carbide (B4C) is a modern ceramic designed as a lightweight, high-hardness material capable of defeating ballistic threats. B4C is the third hardest ceramic known to man and has a density of 2.52 g/cm3. This ceramic is ideal for applications where the areal density is critical. A current issue exists where overmatched projectiles cause catastrophic failure during the impact with B4C. Beyond the elastic limit of the B4C, no additional strength hardening is observed. Recent publications relate this failure to an amorphous shear band. The shear band is formed when the B4C is under compression and carbon atoms are released from the icosahedron, forming free carbon within a shear plane. This layer allows for trans-layer shearing of the icosahedra and collapse of the unit structure. Prior research demonstrates that silicon (Si) is a preferred semimetal for elemental inclusion that can greatly increase the ductility and re-bonding of B4C. The goal of this research is to both determine where the Si inclusion goes within the B4C structure using X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS), and other techniques, and to perform equation of state studies on the materials to determine the variations in physical properties correlated to the inclusion of varied percentages of Si within the B4C.