Engineering materials studies using pulsed neutron diffraction at J-PARC

Harjo, S.; 川崎 卓郎; 相澤 一也; Gong, W.*

no journal, , 

Current status of The Engineering Materials Diffractometer TAKUMI in J-PARC and two research-examples will be introduced. First example is martensite phase stress and the strengthening mechanism in TRIP. The stress evolution in the constituent phases including martensite were directly measured. The stress contribution from martensite to the strength increased with increasing applied true strain, where that from bainitic ferrite was almost unchanged and that from austenite decreased, demonstrating directly that the deformation induced martensitic transformation contribute to the increase in strength. Second example is work hardening, dislocation structure and load partitioning in a lath martensite steel containing 0.22 mass% carbon. Redistributions of the stress and dislocation densities/arrangements occurred in two lath packets: soft packet, where the dislocation glides are favorable, and hard packet, where they are unfavorable.