Atomic displacements in the austenite-martensite transformation

The atomic displacements in the transformation from austenite to martensite are described, and the strains involved are derived. It is shown that the tetragonality of martensite arises as a necessary consequence of the assumption that the iron and carbon atom displacements constitute a common homogeneous deformation. An explanation of the observed high indices of the habit plane of martensite of certain carbon contents is advanced.