REAL-TIME NEUTRON TRANSMISSION INVESTIGATION OF THE AUSTENITE BAINITETRANSFORMATION IN GREY IRON

The first successful application of a new method to investigate phase transformations in real time, like the decomposition of austenite into bainite in grey iron, is described. During the ongoing transformation , transmission spectra of thermal neutrons, which contain Bragg edges corresponding to the crystal structure of the transforming phases, are recorded. By evaluating the height of these Bragg edges, which is a m easure of the volume fraction of the phase, at different transformatio n times, the transformation can be followed in-situ in a time resolved manner. The method is compared to other previously used methods (micr ographs, dilatometry, diffraction techniques); also a summary and an o utlook are given.