Bildung von Martensit aus unterkühltem Austenit, Ablauf der Umwandlung bei sinkender Temperatur. Bevorzugte Orientierungen der Martensitnadeln in ehemaligen Austenitkörnern. Die Umwandlung selbst wird nicht aufgelöst.

The film shows the development of the martensite from the super-cooled austenite in the needle profile, formed by the sudden change of volume, of a polished surface of a chrome-nickel steel under the heating table microscope. The grain boundaries of the high temperature phase of the austenite also become visible. The shots are taken during the cooling off after an austenitisation at 1150 °C. They begin at about 300 °C just above the Ms-temperature, the start of the martensite formation. It can be seen that the austenite-martensite-transformation continues in the form of constantly new plate formation with decreasing temperatures. The development of one particular martensite plate cannot be observed owing to the high speed. The needles lie within a former austenite grain in certain preferred directions.