Bridging scale studies of nanocrystalline steels using pulsed neutron diffraction

Harjo, S.   ; Kawasaki, Takuro   ; Gong, W.*

Hierarchical analyses to bridge-scale the microstructures and the mechanical or functional properties using pulsed neutron diffraction with time-of-flight method are introduced. Pulsed neutron diffraction is suitable for microscopic structural observation as a bulk average behavior because of the high penetration ability of neutron and the simultaneous measurement of multiple Bragg peaks. Careful analysis of the Bragg peaks in a neutron diffraction pattern can reveal important structural details of a sample material such as internal stresses, phase conditions, dislocations, texture etc. The pulsed neutron diffraction with time-of-flight and some research examples focusing on steels with fine grains are introduced. Researches of in situ observations on TRIP steels, a lath martensitic steel or a pearlitic steel during loading are introduces as well as the observation during heat treatments.