Date of Graduation

Spring 2017

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Ridwan Sakidja

Keywords

interatomic potential, molecular dynamics, nanolayers, deformation, metal-ceramic

Subject Categories

Materials Science and Engineering

Abstract

A novel interatomic potential of ternary Al-Ti-N has been developed to study the deformation behavior of Al-TiN nanolaminates. The ternary nanolayered Al-TiN composite has attracted a lot of interest due to its combination of strength and ductility. The current analysis on the system has been primarily concentrated on continuum models which are inadequate to explain the key deformation events such as nucleation and interaction of dislocations. Progress in the preferred atomistic approach has been hampered however by the lack of available interatomic potential optimized for the ternary system. I developed a many-body potential based on embedded atomic model (EAM) by employing the force-fitting code Potfit to sample the energy and force data generated from the ab-initio molecular dynamics simulations of the ternary system using VASP code. The potential's analytical EAM function was subsequently optimized and utilized to simulate structures of bulk Al & TiN and Al-TiN nanolaminates. I then focused on modeling the deformation behavior of Al-TiN multilayers under compression through classical molecular dynamics simulations. I found that the total bilayer thickness as well as volume ratio between TiN and Al nanolayers play a major role in controlling the dislocation nucleation and mobility and the stress accumulation at the layer interface and thus determine the deformation behavior and failure mechanisms of the nanolayered composites.

Copyright

© Paul Simanjuntak

Open Access

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