To study the stability of different sized Al grains in Ni/Fe bulk matrices at temperatures above and below the structure melting point, Molecular Dynamics simulations of respective structures (grain/matrix atom ratio ~1:3) have been carried out using the ReaxFF method under constant-pressure conditions for temperature ranges of 300-3000K and 3000-300K. We observe lower chemical strain energies for Al and Ni in mixed state and completion of mixing at lower temperature than for Al in the Fe matrix. Possibly due to Fe-Fe crystal bond lengths being shorter than Al-Al bond lengths, larger Al grains appear to be favorable for mixing with Fe matrix. However, for Ni matrix smaller Al grains appear to be favorable for mixing, which can be explained by larger interface/mixing area, differences in the heats of formation and Ni-Ni crystal bond lengths being longer than Fe-Fe bond lengths.

MD simulation of Al grain mixing/diffusion in Fe/Ni matrices

244th National Meeting (2012)

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