A Phase-field Model for Computer Simulation of Lamellar Structure Formation in gamma-TiAI

Ivaylo Katzarov, Savko Malinov, Wei Sha

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

In the present paper, a phase-field model is developed to simulate the formation and evolution of lamellar microstructure in γ-TiAl alloys. The mechanism of formation of TiAl lamellae proposed by Denquin and Naka is incorporated into the model. The model describes the formation and evolution of the face-centered cubic (fcc) stacking lamellar zone followed by the subsequent appearance and growth of the γ-phase, involving both the chemical composition change by atom transfer and the ordering of the fcc lattice. The thermodynamics of the model system and the interaction between the displacive and diffusional transformations are described by a non-equilibrium free energy formulated as a function of concentration and structural order parameter fields. The long-range elastic interactions, arising from the lattice misfit between the α, fcc (A1) and the various orientation variants of the γ-phase are taken into account by incorporating of the elastic strain energy into the total free energy. Simulation studies based on the model successfully predicted some essential features of the lamellar structure. It is found that the formation and evolution of the lamellar structure are predominantly controlled by the minimization of the elastic energy of the interfaces between the different fcc stacking groups, low-symmetry product phase γ and the high-symmetry α-phase, as well as between the various orientation variants of the product phase.
Original languageEnglish
Pages (from-to)453-463
Number of pages11
JournalActa Materialia
Volume54(2)
Issue number2
DOIs
Publication statusPublished - Jan 2006

ASJC Scopus subject areas

  • Materials Science(all)
  • Electronic, Optical and Magnetic Materials
  • Metals and Alloys

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