Densification rate influence on nanopowder compactibility


The paper concerns processes of high-speed compaction of nanosized powders. The processes of uniform and uniaxial compaction have been simulated by the granular dynamics method. Nanoparticles interaction, in addition to known contact laws, includes dispersive attraction, formation of a strong interparticle bonding as well as the forces caused by viscous stresses in the contact region. For different densification rates, the densification curves (pressure vs. density) have been calculated. Relaxation of the stresses after the compression stage has been analyzed. The densification curves analysis allows us to suggest the dependence of compaction pressure as a function of strain rate in the form of 1/8 p v ∝ . The rate dependence obtained has been applied for interpretation of experimental data concerning high-speed processes of magnetic pulsed compaction of nanopowders.