Ideas Demo Page

The dynamic pictures on these web pages illustrate some concepts that are central to our work. We are not sure if these demos are actually educational, but they are fun and interactive. They are Java applets, and require a fast Java virtual machine for best results.

Ordered Alloys

Ordered alloys are composed of at least two types of atoms, which alternate in position with some regularity. You can better understand the structures below by rotating them with your mouse.

This particular arrangement of atoms is called the B2 ordered structure. Examples of ordered alloys with the B2 structure are NiAl, FeCo, and CuZn. The B2 structure has simple cubic symmetry, even though its underlying lattice is body-centered cubic. The atoms above are arranged on two interpenetrating simple cubic sublattices. For clarity the two sublattices are drawn below as two interpenetrating wireframes. See if you can rotate these two figures into the same orientations. (Hint: It might be most clear to look at them end-on in the "(100) orientation".) Notice the symmetry of the sublattices -- the structure is the same when the two species of atoms are interchanged between the two sublattices.

Next Java Applet: Vibrational Entropy

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