Metal alloys are very important part of metallurgy and materials science in which the today’s engineering is built upon them. Characteristics of metal alloys can be changed with changed temperature and the compositions of alloy system. In this article we will explain the characteristics of binary phase diagrams with the changing temperature and the changing compositions.
What Is ‘Binary Phase Diagram’ In Metallurgy?
Binary phase diagram is diagram that shows the compositional property and phase change with the changing temperature and the changing compositions of alloys that constitutes two of alloying compositions. One of the greatest examples of these binary phase systems are Nickel-copper system and the iron-carbon systems.

If we take a look at the Nickel-Copper system that tha phase diagram is given above. As you see the vertical axes are giving the temperature informations; the right one is Fahrenheit which is prominent in United States, the left one is Celsius which is also prominent in other countries. The horizontal axis is showing the percent of Nickel inside the Nickel-Copper alloy. For example, if we select the 60 percent from the horizontal axis, this means that, it has 60% of Nickel and 40% of Copper alloy.
At the diagram, there are two lines that represents the Liquid and Solid states of alloy system. And as you see, with the increasing Nickel percent, both Solidus and Liquidus lines are increases. If you select a Nickel percent from horizontal axis, you can take the information about above which temperature this alloy will be completely liquid with Liquidus line, and below which temperature this alloy system will be completely solid with Solidus line. And the temperatures between these lines represent the phase that both liquid and solid phases are exist.
As you see above, you can easily asses the phase situations of given alloy system in specific percent of compositions. And you can see the melting and the freezing temperatures of these alloy systems from binary phase diagrams.
Leave your comments and questions about ‘binary phase diagrams’ below!
Image source: Fundamentals of modern manufacturing
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