The time-of-flight method of neutron diffraction was employed to measure the volume fraction and carbon concentration of the retained austenite in four TRIP-DP steels. The results obtained before and after tensile deformation are compared with those measured by the conventional X-ray diffraction method. It is found that the neutron diffraction method is superior to X-ray in order to evaluate the bulky average of volume fraction because the stress-induced martensitic transformation occurs easily at the surface compared with the interior of a specimen. The stress-induced transformation is influenced not only by carbon concentration but also by microstructural topology.
