Abstract Submitted to the    NANOTUBE'04 Conference:

The elastic properties of BN-nanotubes embedded in amorphous Si-B-N ceramics are examined by molecuar dynamics simulations. To derive stress-strain curves for various tensile and compressive load cases at given temperature and pressure, we use the Parrinello-Rahman approach to apply external stress to a periodic system. In addition to Young moduli and Possion ratios, we compare radial distribution functions, average coordination numbers, ring statistics and self-diffusion coefficients, in order to characterize the short-range, medium-range and long-range order of Si₃BN₅, Si₃B₂N₆ and Si₃B₃N₇ matrices. Here, our results show that Si₃B₃N₇ exhibits the highest Young modulus and the largest elastic range. Furthermore, we calculate stress-strain curves for capped BN-nanotubes and infinite BN-nanotubes embedded in Si-B-N matrices to compare the derived Young modul i with different macroscopic rule-of-mixtures predictions. Here, the influence of the nanotube/matrix ratio and of the temperature on the elastic modulus is examined. Our results show a good agreement with the rule-of-mixtures predictions. In particular, all systems are modeled with a reactive many-body bond order potential due to Tersoff.

References:

[1] M. Griebel, J. Hamaekers, Molecular dynamics simulations of the elastic moduli of polymer-carbon nanotube composites, Computer Methods in Applied Mechanics and Engineering, (2004), Article in Press.