課程名稱︰材料熱力學
課程性質︰必修
課程教師︰高振宏
開課學院：工學院
開課系所︰材料系
考試日期（年月日）︰九十六年五月二日
考試時限（分鐘）：三小時
是否需發放獎勵金：是的，謝謝。
試題 :
1.(20%)The activity coefficient of Zn in liquid Zn-Cd alloy at 435℃
can be represented as
lnγzn=0.875Xcd^2-0.3Xcd^3
Derive the corresponding expression for the dependence of lnγcd on composition
Xcd, and calculate the activity of cadimium in the alloy of Xcd = 0.5 at 435℃
At the temperature, do Zn and Cd atoms like or dislike each other?
2.(20%)The phase diagram for A-B is show below（Gaskell課本4th ed p295 figure
10.21 f）. Schematically sketch the free energy versus composition diagram
for the A-B system at T1(全部都是溶液) T2(穿過兩個固液共存線) T3(固相不互溶)
and T4=(T2+T3)/2
3.(20%)A solution exhibits the sub-regular solution behavior with deltaHmix
=x1x2(4850x1+12300x2) J/mol
(a)Derive the equation for the boundry ofr the spinodal region. Express
your equation in terms of x2 and T.
(b)find the critical temperature and critical composition for the miscibility
gap of the solution.
4.(20%)Cao and Mgo form a simple eutectic system with limited ranges of
solid solubility. The eutectic temperature is 2370℃。Assuming that the
solutes in the two solid solutions obey Henry's law with γcao in MgO=12.88
and γmgo in CaO=6.23 at 2300℃, calculate the solutibility of CaO in MgO
and the solubility of MgO in CaO at 2300℃.
5.(20%)The system AB is a regular solution and can be described by the
quasichemical model. The heat of vaporization of pure A is 98700(J/mole);
that of pure B is 12700(J/mole). At a solution composition xb=0.4 at 750K
, the activity of component a is found to be 0.53. Calculate the bond
energy of AB εab in the system. Note: Both A and B have the FCC crystal
struture. The bond energy εaa and εbb can be estimated directly from
their respective heat of vaporization.
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這個小孩好奇怪。
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