Large-scale molecular dynamics studies of sliding friction in nanocrystalline aluminum

ORAL

Abstract

We present the results of 138 million-atom and 1.8 billion-atom non-equilibrium molecular dynamics (NEMD) simulations for Al-Al sliding friction at pressures of 15 GPa. Three-dimensional samples comprised of 4 nm, 20 nm and 50 nm grains were studied to times of 100 ns for the largest systems. We discuss the evolution of the initial grain size distribution to a steady state distribution that is statistically similar for all initial grain sizes. We compare the results for the frictional force to a rate dependent model that incorporates plasticity and discuss the relationships among grain size, grain morphology, dislocations and other defect structures, and plasticity.

*This work was performed under the auspices of the U.S. Dept. of Energy under contract DE-AC52-06NA25396. The support of the LANL ASC-PEM program gratefully acknowledged.

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Authors

  • Tim Germann

    • Los alamos National Lab
    • Los Alamos National Laboratory
    • Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM

  • Ramon Ravelo

    • University of Texas - El Paso
    • Physics Department, University of Texas, El Paso TX
    • University of Texas- El Paso

  • James Hammerberg

    • Los Alamos National Laboratory
    • Los Alamos National Laboratory, NM