第 20 卷第 2 期 中国有色金属学报 2010 年 2 月
Vol.20 No.2 The Chinese Journal of Nonferrous Metals Feb. 2010
文章编号:1004-0609(2009)08-0313-05
二元相图中两个被疏忽的问题
唐仁政,田荣璋
(中南大学 材料科学与工程学院,长沙 410083)
摘 要:目前在二元相图中普遍存在两个被疏忽的问题:一是关于二元系中许多中间相在某一温度发生晶型转变
时如何表示的问题,在已发表的二元相图资料中,大部分用水平实线或虚线来表示这种晶型转变,而二元相图中
水平实线或虚线通常是用来表示三相平衡的等温反应,但中间相的晶型转变不是三相平衡的等温反应,所以,不
能用实线或虚线来表示;二是对某些沸点较低的组元,在温度高于其沸点温度时,靠近这些组元的端际单相区应
该是气相,而许多二元相图中仍然标为液相。本文作者认为应该重视由于疏忽而产生的这两类问题,并加以改正,
以免让读者产生误解。
关键词:二元相图;中间相晶型转变;液−气相态转变
中图分类号:TG113.14 文献标识码:A
Two problems overlooked in binary phase diagrams
TANG Ren-zheng, TIAN Rong-zhang
(School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: Two usually over looked problems are in the binary phase diagrams. First, the crystal style of many interphases
would transit in the binary systems, the crystal style transition was shown by horizontal full line or dashed line in most of
the published binary phase diagrams. Horizontal full line in binary phase diagram presents the isothermal reaction of
three-phase equilibrium. But crystal shape transition of the interphase is not an isothermal reaction of three-phase
equilibrium, therefore it can not be presented by horizontal full line or dashed line. Second, to some components with low
boiling point, when the temperature is higher than their boiling points, the head monophase field next to the components
should be gas phase, which was still marked as liquid phase in many binary phase diagrams. This is also an missing error.
The author suggests that the two neglected problems should be paid great attention and corrected to avoid
misunderstanding.
Key words: binary phase diagram; interphase crystal shape transition; liquid-gas phase state change
众所周知,相图是描述由热力学参数反映的体系
相平衡的图形表达形式。对于相图中的相区,相线之
间的关系都必需符合热力学的基本规律。二元相图是
最基本的且应用最广的相图,其基本规律为大家所熟
知。但最近本文作者发现在众多已发表的二元相图中,
普遍存在下述两个问题,严格地说这是一违反热力学
规律的错误。
1 中间相存在晶型转变时在相图中
的表示方法
在二元系中有许多中间相,在温度变化时存在晶
型转变,这种晶型转变对于固定成分的中间相,是
收稿日期:2009-03-09;修订日期:2009-07-30
通讯作者:唐仁政,教授;电话:0731-88879868;E-mail: csutrz@126.com