当前课程知识点:Fundamentals of Inorganic Materials Science > 5 Phase equilibrium > 5.6 Ternary diagrams > 5.6.3 (3) Basic types of ternary phase diagrams
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下面我们来学习第3类三元相图
看相图下方
我们知道这是生成一个固相分解的二元化合物的三元系统相图
图中三个无变量点
根据重心规则
P点对应的副三角形为ACS
P点位于△ACS的交叉位
所以是单转熔点
L将A转熔
生成 S+C
and form S + C
E点对应的副三角形为△BCS
且位于重心位
所以E是低共熔点
此点液相L
同时析出 S+C+B
我们着重看R点
包围R点的初晶区为ASB
但是连接ASB并不能构成一个三角形
而是一条直线
那么R点是什么点呢
R点为过渡点
L+A+B生成S
实质是
A和B发生固相反应生成S
L起介质作用
这个相图中三个无变量点
画出了两个副三角形
印证了我们前面讲过的无变量点的个数
大于等于副三角形的个数
我们再来看线
通过切线规则
确定PR线为转熔线
L+A生成S
知道了点线的含义
现在我们分析1点的析晶路程
点1位于A的初晶区
所以首先连接A1并延长
液相将不断地析出晶体A
直到D点
D点位于转熔线上
所以这个时候发生转融
将A转融掉生成S
液相点移动到N点时
固相点移动到S点
说明此时晶体A消失
所以转融不再发生
液相点将穿过S的初晶区
发生穿晶现象
当液相点到F点时
开始析出晶体C和S
走到E点
同时析出BCS
固相点移动到和系统组成点重合
析晶结束
下面我们来看具有一个一致熔融三元化合物的三元系统相图
这个相图的特点是S的组成点在其初晶区内
系统可划分为三个分系统
这个相图比较简单
我们就不再详述了
接下来
我们看具有不一致熔融三元化合物的三元系统相图
相图中三元化合物S的组成点位于其初晶区以外
因而是一个不一致熔化合物
这个相图希望大家在课后加以分析
按照我们分析生成不一致熔融二元化合物相图的方法
同学们在划分副三角形后
根据重心规则判断无变量点的性质
用连线规则和重心规则在界线上标示单箭头和双箭头
最后按照前面我们讲过的方法分析析晶路线
我们学习了六类三元系统基本类型相图
现在总结一下分析复杂相图的主要步
判断化合物的性质
根据化合物组成点是否落在其初晶区内
判断化合物性质属一致熔或不一致熔
另外
化合物组成点如果落在浓度三角形内
为三元化合物
若在三条边上就为二元化合物
划分副三角形
根据无变量划分副三角形
如果5个无变量点
最多画出5个副三角形
应用连线规则判断界线上温度下降的方向
第4步
应用切线规则判断界线的性质
注意一条界线上可能既有共熔性质又有转熔性质
五根据重心规则确定无变量点的性质
最后
分析冷却析晶过程
要牢记固相点
液相点
系统组成点
始终保持三点一线
到此为止
我们把三元系统相图的基本类型给大家讲解完了
为了能够应用专业相图
我们大家课后一定要认真复习
掌握分析三元相图的重要规则及步骤
这次课就到这里
同学们再见
-Test for chapter 1
-2.1 Type of defect
-2.2.1 The expression methods of point defects
--2.2.1 The expression methods of point defects
--2.2.1 The expression methods of point defects
-2.2.2 The rules for writing of defect reaction equation
--2.2.2 The rules for writing of defect reaction equation
--2.2.2 The rules for writing of defect reaction equation
-2.3 Calculation of thermal defect concentration
--2.3 Calculation of thermal defect concentration
--2.3 Calculation of thermal defect concentration
-2.4 Non-stoichiometric compounds
--2.4 Non-stoichiometric compounds
--2.4 Non-stoichiometric compounds
-Homework for chapter 2
-Test for chapter 2
-3.1 The classification of solid solutions
--3.1 The classification of solid solutions
--3.1 The classification of solid solutions
-3.2 Substitutional solid solution
--3.2 Substitutional solid solution
--3.2 Substitutional solid solution
-3.3 Interstitial solid solution
--3.3 Interstitial solid solution
--3.3 Interstitial solid solution
-3.4 The research method of solid solutions
--3.4 The research method of solid solutions
--3.4 The research method of solid solutions
-3.5 Questions for crystal imperfection and solid solution
--Questions for crystal imperfection and solid solution
-Homework for chapter 3
-Test for chapter 3
-4.1 Melt structure
-4.2 The properties of the melt
--4.2.1 The properties of the melt_viscosity
--4.2.2 The properties of the melt_surface tension
--4.2 The properties of the melt
-4.3 The characteristics of glass
--4.3 The characteristics of glass
--4.3 The characteristics of glass
-4.4 The formation of glass
--4.4.1 The formation of glass_kinetics conditions
--4.4.2 The formation of glass_crystal chemical conditions
-4.5 The structure of glass
-4.6 The typical glass
-4.7 Questions for melt and glass
--Questions for melt and glass
-Test for chapter 4
-5.1 Phase equilibrium in silicate systems
--5.1 Phase equilibrium in silicate system
--5.1 Phase equilibrium in silicate system
-5.2 One-component system phase diagram
--5.2 One-component system phase diagram
--5.2 One-component system phase diagram
-5.3 Applications of one-component diagrams
--5.3 Applications of one-component diagrams
--5.3 Applications of one-component diagrams
-5.4 Binary diagrams
--5.4.1 Binary diagram with eutectic point
--5.4.2 Binary system with a congruent melting compound and one with an incongruent melting compound
--5.4.3 Other five types of phase diagrams of binary systems
-5.5 Applications of binary phase diagrams
--5.5 Applications of binary phase diagrams
--5.5 Applications of binary phase diagrams
-5.6 Ternary diagrams
--5.6.1 Representation of ternary system composition
--5.6.1 Representation of ternary system composition
--5.6.2 Three-dimensional state diagram and plane projection diagram of a simple ternary system
--5.6.2 Three-dimensional state diagram and plane projection diagram of a simple ternary system
--5.6.3 (1) Basic types of ternary phase diagrams
--5.6.3 (2) Basic types of ternary phase diagrams
--5.6.3 (3) Basic types of ternary phase diagrams
--5.6.3 Basic types of ternary phase diagrams
-5.7 Applications of ternary phase diagrams
--5.7 Applications of ternary phase diagrams
--5.7 Applications of ternary phase diagrams
-5.8 Research methods of phase equilibrium
--5.8 Research methods of phase equilibrium
--5.8 Research methods of phase equilibrium
-5.9 Questions for phase equilibria
--Questions for phase equilibria
-Homework for chaper 5
-Test for chapter 5
-6.1 Overview of diffusion
-6.2 The kinetic equations of diffusion
--6.2 The kinetic equations of diffusion
--6.2 The kinetic equations of diffusion
-6.3 The thermodynamic equation of diffusion
--6.3 The thermodynamic equation of diffusion
--6.3 The thermodynamic equation of diffusion
-6.4 Diffusion mechanisms and diffusion coefficient
--6.4 Diffusion mechanisms and diffusion coefficient
--6.4 Diffusion mechanisms and diffusion coefficient
-6.5 Diffusion in solid
-6.6 Factors affecting diffusion
--6.6 Factors affecting diffusion
--6.6 Factors affecting diffusion
-6.7 Questions for diffusion
-Homework for chaper 6
-Test for chapter 6
-7.1 Overview of solid state reactions
--7.1 Overview of solid state reactions
--7.1 Overview of solid state reactions
-7.2 Kinetic equation of solid state reaction
--7.2 Kinetic equation of solid state reaction
-7.3 Factors affecting the solid state reaction
--7.3 Factors affecting the solid state reaction
--7.3 Factors affecting the solid state reaction
-Homeword for chapter 7
-8.1 The categories of phase transformation
--8.1 The categories of phase transformation
--8.1 The categories of phase transformation
-8.2 Crystallization
--8.2.1 Crystallization thermodynamics
--8.2.2 Crystallization kinetics
-8.3 Phase Separation of glass
--8.3 Phase separation of glass
--8.3 Phase separation of glass
-8.4 Questions for phase transformation
--Questions for phase transformation
-Test for chapter 8
-9.1 Overview of sintering
-9.2 The driving forces and models of sintering
--9.2 The driving forces and models of sintering
--9.2 The driving forces and models of sintering
-9.3 Solid state sintering
--9.3.1 Evaporation-Condensation mass transfer
--9.3.2 Diffusion mass transfer
-9.4 Liquid phase sintering
--9.4.2 Solution-Precipitation mass transfer
-9.5 Grain growth and secondary recrystallization
--9.5.2 Secondary recrystallization
--9.5 Grain growth and secondary recrystallization
-9.6 Factors affecting sintering
--9.6 Factors affecting sintering
--9.6 Factors affecting sintering
-9.7 Questions for sintering
-Homework for chapter 9
-Test for chapter 9