Demonstration of Coincidence Site Lattice

H. K. D. H. Bhadeshia

A coincidence-site lattice is constructed by taking two lattices with a common orgin, and allowing them to pentrate all space; coincidence points are those lattice points common to the two lattices. This model shown below reproduces this effect in two dimensions. Two circular grids connected at the centre. The grids are first aligned to indicate a single crystal. Rotating one with respect to the other produces a variety of coincidence site lattices, even when the angle of rotation is large. This model is place on an overhead projector. The effect can also be seen on movies:

Quicktime movies showing the deformation process: Movie 1 (200 kBytes); Movie 2 (6 MBytes).

MPG movies showing the deformation process: Movie 3 (200 kBytes)

coincidence-site lattice coincidence-site lattice
The pattern shows coincidence points between the two grids which are rotated with respect to each other. The pattern shows coincidence points between the two grids which are rotated with respect to each other.
 

Superalloys Titanium Bainite Martensite Widmanstätten ferrite
Cast iron Welding Allotriomorphic ferrite Movies Slides
Neural Networks Creep Mechanicallly Alloyed Theses Retained Austenite
Kirkendall Dendrites Cementite Thermodynamics Kinetics
Stainless Steel TRIP Steels Thermal Analysis Teaching Finite Elements


PT Group Home Materials Algorithms Any Valid CSS!