S.J.T.0. Phase Transformation and Applications 固液完全互溶 的体系 T G G r (a) (b) SJTU Thermodynamics of Ma 图6-9两组元完全互溶的相图
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 16 Phase Diagram III Page 6/40 固液完全互溶 的体系
Sn-Bi S.J.T.0. Phase Transformation and Applications Page 7/40 Weight Percent Bismuth 300 30 20 30 40 60 60 70 0 90 100 Sn中溶有 271A42*℃ B形成固 250 231.9681℃ L 溶体 200 自由度2 150 138℃ 13 1D0 (Bi) 溶解度变化很 50 大！ (aSn) 0 203040600000 20 30 70 0 100 Sn Atomic Percent Bismuth Bi SJTU Thermodynamics of Materials Fall 2011 @X.J.Jin Lecture 16 Phase Diagram Ill
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 16 Phase Diagram III Page 7/40 Sn-Bi Sn中溶有 Bi形成固 溶体 自由度2 溶解度变化很 大！
Spinodal Points S.J.T.0. Phase Transformation and Applications Page 8/40 Spinodal points A special significance in the study of phase transformations 1050 GM -RT(1+)-20=0 1000 XA XB 号气 850 Spinodal RT 800 line XAXB 750 2而 -,1000m 700 1+a2 650 600 0.25 0.75 Figure 9.15 The miscibility gap,showing spinodal line SJTU Thermodynamics of Materials Fall 2011 @X.J.Jin Lecture 16 Phase Diagram Ill
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 16 Phase Diagram III Page 8/40 Spinodal points A special significance in the study of phase transformations ) 2 0 1 1 ( 2 2 = + − = ⎟⎟⎠⎞ ⎜⎜⎝⎛ ∂∂ ϖ B T A B M x x RT xG 2ϖ RT x xA B = Spinodal Points
S.J.T.0. 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 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 Fall 2011 X.J.Jin Lecture 16 Phase Diagram Ill
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 16 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
存在溶解度间隙的相图 S.J.T.0. Phase Transformation and Applications Page 10/40 非理想 1050 1000 规则溶液 950- 900 850 1 Spinodal a2 相律 800 line 750 700 c1+c2 650 600 0 0.25 0.5 0.75 A 相→ Figure 9.15 The miscibility gap,showing spinodal line. SJTU Thermodynamics of Materials Fall 2011 @X.J.Jin Lecture 16 Phase Diagram Ill
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 16 Phase Diagram III Page 10/40 存在溶解度间隙的相图 非理想 规则溶液 相律