Displacements caused by martensitic transformation - hot stage microscopy

Source: Wirtschaftsvereinigung Stahl, Düsseldorf. Hot-stage optical microscopy showing the displacements due to the disciplined motion of atoms during the athermal formation of martensite during the cooling of a steel. The commentary is in German, but translates roughly as follows: The polished surface of a steel can be observed during cooling, in a microscope with a hot-stage. The sample is austenitised and then cooled. The polished surface is altered by the formation of martensite plates. At 380 C, only