纳米W粉冲击烧结的分子动力学模拟

Shock consolidation of powders is an effective method for fabrication of the high quality tungsten, and molecular dynamics simulation has unique advantages in modelling the rapid process at atomic-scale. In this work, the shock consolidation of nano tungsten powders at room temperature was studied by molecular dynamics using the embedded atomic potential of tungsten. The morphology of the compressed particles, distribution of particle velocity, p-U_p, T-U_p, T-p curves and radial distribution function were investigated to analyze the effects of particle velocity and jets on the shock consolidation. The mechanism of consolidation was also proposed at micro-scale. The results showed that the nanoparticles could not be compacted to full density at a relatively low impact velocity (<500 m/s), while a good densification could be achieved at high impact velocity (>1 000 m/s); the high pressure due to the extrusion between particles leads to flow and deformation on the surface of the particle. The voids among the particles were filled by the flowing atoms, leading to densification. Particles were melted during the impacts by adjacent particle and jet, which promotes the sintering between particles.