Although computer simulation has played a central role in the study of nucleation and growth since the earliest molecular dynamics simulations almost 50 years ago, confusion surrounding the effect of finite size on such simulations have limited their applicability. Modeling solidification in molten tantalum on the BlueGene/L computer, I will discuss the first atomistic simulations of solidification that demonstrate independence from finite size effects during the entire nucleation and growth process, up to the onset of coarsening. For the conditions of our simulations, we show that systems larger than about 8,000,000 atoms are necessary to model nucleation and growth with no finite size dependence, whereas smaller simulations can be described using finite size scaling theory. Our results indicate that simulations at slower strain rates (or with differing materials) may require even larger system sizes, driving us towards peta-scale computing.
UCRL-ABS-221020 THis work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.