9.1 Freezing Point Depress4ion(4) S.J.T.0. Phase Transformation and Applications Page 17/36 The liquid solution is in equilibrium with 稀溶液的依数性 the pure solid, =1 10 QA.L.pure AG-L(T-T)+RTIn a1,solutionO T>x To a1.pure L(T,-T)=-RTInXAJ.olon ideal solution To If T is close to the Tm InxAl,solution L(T-T) RTH A XB→ B Melting point depression Fig.9.2 Plot of the activity of Aiquid △T=Tm-T at T<TmAversus composition. XB L(T-T) ln(1-z）=-z small z RTH SJTU Thermodynamics of Materials Fall 2011 ©X.J.Jin Lecture 14 Phase diagram IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2011 © X. J. Jin Lecture 14 Phase diagram I Page 17/36 9.1 Freezing Point Depress4ion (4) Fig. 9.2 Plot of the activity of Aliquid at T < Tm,A versus composition. A B 1.0 a A (liquid) xB asolid=1 aA,l,pure=1 The liquid solution is in equilibrium with the pure solid, ln 0 ( ) , , + = − Δ = l pure l solution m m a a RT T L T T G If T is close to the Tm RT x ideal solution T L T T A l solution m m , , ln ( ) = − − , , 2 ( ) ln m m A l solution RT L T T x − = − 2 ( ) m m B RT L T T x − = z z small z T Tm T − = − Δ = − ln(1 ) Melting point depression 稀溶液的依数性 T ↔ x