Molecular Dynamics Simulation of the Kinetic Reaction of Nickel and Aluminum Nanoparticles

Report No. ARL-TR-5134
Authors: Brian J. Henz, Takumi Hawa, and Michael Zachariah
Date/Pages: March 2010; 36 pages
Abstract: Molecular dynamics simulations are used to simulate the kinetic reaction of nickel (Ni) and aluminum (Al) particles at the nanometer scale. The effect of particle size on reaction time and temperature for separate nanoparticles is considered as a model system for a powder metallurgy system. Coated nanoparticles in the form of Ni-coated Al nanoparticles and Al-coated Ni nanoparticles are also analyzed as a model for nanoparticles embedded within a matrix. The differences in melting temperature and phase change behavior, e.g., the volumetric expansion of Al between Al and Ni is expected to produce differing results for the coated nanoparticle systems. For instance, the volumetric expansion of Al upon melting is expected to produce large tensile stresses and possibly rupture in the Ni shell for Ni-coated Al. Simulation results showed that the sintering time for separate and coated nanoparticles was nearly linearly dependent upon the number of atoms or volume of the sintering nanoparticles. We also found that nanoparticle size and surface energy was an important factor in determining the adiabatic reaction temperature for both systems at nanoparticle sizes of less than 10 nm in diameter.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2010