| 材料科學導論 |
| 1. 基本定義: |
| A. 相律 (相、成分與自由度) |
 系統
(system) |
| 定義—
Any portion of the material universe which can be isolated completely
and arbitrarily from the rest for consideration of the changes which may occur within it under varying conditions. |
| 例如—the
binary system CaO-Al2O3 the ternary system K2O-B2O3-H2O |
| 相
(P, phase) |
| 定義—
Any portion of a system which is physically homogeneous within itself
and bounded by a surface so that it is mechanically separable from any other portions. |
| Homogeneous: 系統僅由一相組成。 |
| Heterogeneous: 系統由多相組成。 |
| 成分
(C, composition) |
| 定義—
The smallest number of independently variable chemical constituents necessary
and sufficient to express the composition of each phase present in any state of equilibrium. |
| (在表示一個相的化學組成時，允許使用零或負數的成分。) |
| 自由度
(F, degree of freedom, or variance) |
| 定義—
The number of intensive variables which can be altered inde-pendently and
arbitrarily without bring about the disappearance of a phase or the formation of a new one. |
| intensive variable : 與質量和系統大小無關的變量。例如: P,T,化學組成等。 |
| invariant : F = 0 |
| mono-variant : F = 1 |
| bi-variant : F = 2 |
| tri-variant : F = 3 |
| 相律
(phase rule) |
| P + F = C + 2 (口訣：police force = cops + 2) |
| 當系統是一個condensed system時，相律會成為： |
| P + F = C + 1 |
| B. 相律的限制 |
| 只適用於一系統的平衡狀態。 |
| 只與成分和相的數目有關。 |
| 與各成分的本質無關，與各相的數量和本質也無關。 |
| 不能告訴我們反應的速率。 |
| C. 與微構造的關係 |
| 2. 單成分系統 (one-component system) 相圖 |
| 水的相圖 |
| 硫的相圖 |
| 3. 雙成分系統 (two-component [binary] system) 相圖 |
| 連接線
(tie line) |
| 槓桿原理
(lever rule) |
| 各種invariant
( F = 0)反應情況(常見的三相反應) |
| Monotectic (偏晶反應) |
| Monotectoid (偏析反應) |
| Eutectic (共晶反應) ─ 最重要而常見。 |
| Eutectoid (共析反應) |
| Syntectic (同熔反應) |
| Peritectic (包晶反應) |
| Peritectoid (包析反應) |
| 微構造與相圖的關係 |
| 以Ag-Cu相圖為例。 |
| 以Fe-C相圖為例。 |
| - Fe (BCC) ferrite (肥粒鐵) |
| - Fe (FCC) austenite (沃斯田鐵) |
| - Fe3C cementite (雪明碳鐵) |
| - Fe + Fe3C pearlite (波來鐵) |
| 4. 三成分系統 (three-component [ternary] system) 相圖 |
| 三成分相圖的化學組成表示法 |
| 三成分相圖的立體透視圖 |
| 5. 相圖的製作 |
| A.
計算 – 簡單系統。 |
| B. 實驗 |
| 三種判斷反應是否達到平衡的方法: |
| (1) 時間 (2) 雙向反應 (3) 不同實驗步驟 |
| C. 容易犯的錯誤 |
| 四種基本規則: |
| (1) 相律 (The Phase Rule) |
| (2) 邊界規則 (The Boundary Rule) |
Any
p-phase region can be bounded only by regions containing p  1
phases |
| (3) 邊界曲線規則 (The Boundary-curvature Rule) |
| •
Boundaries of one-phase regions must meet with curvatures such that the
boundaries extrapolate into the adjacent two-phase regions. |
| •
The included angle within a one-phase region between two boundaries of the
region must be less than 180o at the intersection of the boundaries. |
| (4) 溶解度規則 (The Solubility Rule) |
| All components are soluble to some degree in all phases. |
 Tie
line和槓桿原理 (lever rule) |
 問
題：熱力學相圖是不是一定正確？ |
| 問
題：熱力學相圖用來判定各種生成相種類的先決條件？ |
| 問
題：熱力學相圖是怎麼製作出來的？ |