title: Coarsening in polycrystalline material using quaternions.
abstract: We develop a phase field model to study the phenomenon of recrystallization and grain coarsening in polycrystalline material. A unique feature of our model is that it can time-evolve the actual orientation field of a material, expressed in terms of quaternions, a four-dimensional non-conserved vector field. The quaternions evolve in time following a Langevin dynamics. The free energy that drives the evolution contains bulk energy for various preferred grain types and anisotropic grain boundary energy. As a proof of principle for the new formalism we show that the average grain size (L) follows the usual L ∼t(1/2) scaling law when the grain boundary energy is independent of the misorientation angle between neighboring grains, whereas the scaling exponent is less (∼0.42) when the grain boundary energy follows the misorientation-dependent, phenomenological Read-Shockley formula.
authors.affiliation: Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India.
authors.forename: Santidan
authors.initials: S
authors.lastname: Biswas
authors.forename: Indradev
authors.initials: I
authors.lastname: Samajdar
authors.forename: Arunansu
authors.initials: A
authors.lastname: Haldar
authors.forename: Anirban
authors.initials: A
authors.lastname: Sain
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D007477:Ions / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D044367:Phase Transition; D013499:Surface Properties
chemical_list: D007477:Ions; D046911:Macromolecular Substances