Overview Here

A phase diagram summarizes the thermodynamic stability of a multi-component alloy. In other words, it tells us how the atoms inside of an alloy react to changing temperature and/or pressure. They are of crucial importance to materials discovery and design because they provide information about the crystal structure stability.

Steel is a very well-known material in the construction industry. It is an alloy composed of Iron (Fe) and Carbon (C). (See the phase diagram for steel here). If this is the first time you’ve seen a diagram like this it’s probably hard to understand. Notice that the horizontal axis is labeled “Carbon, \%” and the vertical axis is labeled “T” in Fahrenheit. This diagram gives us information about what crystal structure will form at a given composition (horizontal axis) and temperature (vertical axis).

One way to determine the phase diagram for a system is to construct the alloy and then use experimental techniques (X-ray diffraction, electron microscopes, etc.) to figure out where the atoms are. This is the work of a metallurgist.

Another way to determine the phase diagram for an alloy is by simulating the interaction between the atoms on a computer. These kinds of studies are a boon to metallugists. Without the computational work, they wouldn’t even know where to look.

Much experimental information exists for binary (two atom types) alloy systems. The same cannot be said for ternary alloys (three atom types). Here is a ternary phase diagram for Fe-Cr-Ni so you can see what they look like. Here’s a fun question: How many ways are there to combine three different atom types among the ~118 elements on the periodic table? Answer: over 260,000 alloy systems. This research project involves choosing one of those alloy systems and using computer calculations and simulations to determine it’s phase diagram. If you choose this project, along the way you will learn:

  1. Crystal Structure
  2. Python
  3. Unix Command line
  4. Thermodynamics of materials.
  5. Git
  6. Latex
  7. Ternary phase diagrams

and more.

Getting Started

To get started on this project, complete the following:

  1. Read Chapters 1 and 2 “Solid State Physics for Advanced Undergraduates” by Hardold Stokes and do all of the problems:
  2. Study about phase diagrams:

  3. Learn about Git. Here is a tutorial. There are others out there and you are welcome to try any of them.

  4. Complete the getting started page.
  5. Install software.
  6. Perform your first materials calculation