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Spinodal Decomposition

Phase Transformations. Spinodal Decomposition. Byeong-Joo Lee POSTECH-MSE. Introduction. Refs: J.W. Cahn : Acta Met. 7, 795 (1961); J. Chem. Phys. 42, 93 (1965); Trans. AIME, 242, 166 (1968) J.E. Hilliard, "Phase Transformations," ASM (1970)

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Spinodal Decomposition

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  1. Phase Transformations Spinodal Decomposition Byeong-Joo LeePOSTECH-MSE

  2. Introduction Refs: J.W. Cahn : Acta Met. 7, 795 (1961); J. Chem. Phys. 42, 93 (1965); Trans. AIME, 242, 166 (1968) J.E. Hilliard, "Phase Transformations," ASM (1970) ► Historically, initiated in an effort to explain uniform distribution of CuAl2 precipitates in Al-Cu alloys. ► Consider the Gibbs energy curve and stability of matrix phase against infinitesimal fluctuation of concentration. ○ Region I · stable against small local fluctuation (nothing happens) large fluctuation → nucleation of β small in extend, large in degree, "Nucleation & Growth Mechanism" ○ Region II · unstable against small local fluctuation (decrease in total energy) spontaneously goes to more fluctuation small in degree, large in extend, "Uphill Diffusion", relatively periodic microstructure

  3. Mathematical Formulation - Thermodynamics of Spinodal Decomposition

  4. Mathematical Formulation - Thermodynamics of Spinodal Decomposition

  5. Mathematical Formulation - Thermodynamics of Spinodal Decomposition

  6. Mathematical Formulation - Thermodynamics of Spinodal Decomposition ► existence of minimum in wave length : for the balance between bulk energy and interfacial energy

  7. Kinetics of Spinodal Decomposition - Diffusion Equation

  8. Kinetics of Spinodal Decomposition - Diffusion Equation

  9. Kinetics of Spinodal Decomposition - Diffusion Equation

  10. Kinetics of Spinodal Decomposition - Diffusion Equation

  11. Kinetics of Spinodal Decomposition - Solution of Diffusion Equation

  12. Kinetics of Spinodal Decomposition - Solution of Diffusion Equation

  13. Appendix - Euler’s Equation: Marion Chap. 6

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