S.J.T.U. Phase Transformation and Applications ge9/40 Gibbs free energy of mixing curve is concave downward In this region the solution may begin the process of decomposition into the equilibrium phases by incremental changes in composition without increasing the total Gibbs free energy of the system. To the left of the spinodal point The transformation is discontinuous △Gm Spinodal point 8→ Figure 9.16 The relation between Gibbs free energy of mixing and composition on either side of spinodal point. To the right of the spinodal point The transformation is continuous XB SJTU Thermodynamics of Materials Spring2o08©X.J.Jin Lecture 17 Phase Diagram IllPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 17 Phase Diagram III Page 9/40 Gibbs free energy of mixing curve is concave downward In this region the solution may begin the process of decomposition into the equilibrium phases by incremental changes in composition without increasing the total Gibbs free energy of the system. To the left of the spinodal point The transformation is discontinuous To the right of the spinodal point The transformation is continuous xB