Characterization of interfacial bonding strength at Al(Si)/diamond interfaces by neutron diffraction: Effect of diamond surface termination and processing conditions

Interfacial bonding plays a vital role and is of eminent importance for thermo-physical and mechanical properties in particulate and fibrous composites. Moreover, the formation of interfacial carbides in the reactive system Al/diamond dominates the thermal and mechanical response. The amount of interfacial carbides can be controlled by the nominal composition of the matrix and process parameters like contact times between the liquid aluminium and the diamond particles during and the surface termination of the diamonds before the liquid metal infiltration processing. Neutron diffraction experiments were performed to study the influence of those parameters on interfacial bonding strength and show a direct correlation between thermo-physical properties, concentration of interfacial aluminium-carbide Al4C3 and micro strain concentrations during neutron diffraction experiment. Furthermore, the oxygenation of the diamond particle surface has a major contribution to the interfacial bonding and thermal conductivity of the composites, respectively. This effect, however, almost diminishes when Al3Si is used as a matrix.