Atomistic Analysis of Phase Segregation Patterning in Binary Thin Films Using Applied Mechanical Fields

The patterned compositional evolution in thin films of a binary alloy controlled by modulated stress fields is studied by employing Monte Carlo simulations. General features of stress-patterned phase segregation are probed using a binary Lennard-Jones potential in which the lattice misfit between the two components of the alloy is varied systematically. In general, patterning of the microstructure is found to be more robust in the low-mismatch binary systems because large lattice mismatch promotes plastic, and therefore, irreversible relaxation, during annealing. It is shown that some control over the relaxation process can be achieved by careful design of the applied thermal annealing history. Additional calculations have been performed using two other potentials for binary metallic systems, an embedded-atom method (EAM) potential for Cu–Ag and a modified embedded-atom method (MEAM) potential for Cu–Ni that represent examples of high and lowmismatched systems, respectively. The results obtained with generic Lennard-Jones potentials are in excellent agreement with those from the EAM and MEAM potentials suggesting that it is possible to derive general guidelines for accomplishing stress-patterned segregation in a variety of thin films of binary alloys. Disciplines Biochemical and Biomolecular Engineering | Chemical Engineering | Engineering Comments Suggested Citation: Nieves, A.M., V. Vitek and T. Sinno. "Atomistic analysis of phase segregation patterning in binary thin films using applied mechanical fields." Journal of Applied Physics. 107, 054303. © 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics and may be found at http://dx.doi.org/10.1063/ 1.3309480. This journal article is available at ScholarlyCommons: http://repository.upenn.edu/cbe_papers/131 Atomistic analysis of phase segregation patterning in binary thin films using applied mechanical fields Alex M. Nieves, V. Vitek, and T. Sinno Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA Received 2 September 2009; accepted 9 January 2010; published online 2 March 2010 The patterned compositional evolution in thin films of a binary alloy controlled by modulated stress fields is studied by employing Monte Carlo simulations. General features of stress-patterned phase segregation are probed using a binary Lennard-Jones potential in which the lattice misfit between the two components of the alloy is varied systematically. In general, patterning of the microstructure is found to be more robust in the low-mismatch binary systems because large lattice mismatch promotes plastic, and therefore, irreversible relaxation, during annealing. It is shown that some control over the relaxation process can be achieved by careful design of the applied thermal annealing history. Additional calculations have been performed using two other potentials for binary metallic systems, an embedded-atom method EAM potential for Cu–Ag and a modified embedded-atom method MEAM potential for Cu–Ni that represent examples of high and low-mismatched systems, respectively. The results obtained with generic Lennard-Jones potentials are in excellent agreement with those from the EAM and MEAM potentials suggesting that it is possible to derive general guidelines for accomplishing stress-patterned segregation in a variety of thin films of binary alloys. © 2010 American Institute of Physics. doi:10.1063/1.3309480