Topological Approach to Ferrite Martensite Dualphase Microstructures.pdf

ISIJ International, Vol. 52 (2012), No. 7, pp. 1362–1365 Topological Approach to Ferrite/Martensite Dual-phase Microstructures 1) 2) 3) 4) Naoko SATO, Yoshitaka ADACHI, Hiroyuki KAWATA and Kenji KANEKO 1) Graduate Student of Kyushu University, 744 Motooka, Nishiku, Fukuoka, 819-0395 Japan. E-mail: sato@zaiko13.zaiko. kyushu-u.ac.jp 2) Department of Mechanical Engineering, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890- 8580 Japan. E-mail: adachi@mech.kagoshima-u.ac.jp 3) Kimitsu RD Laboratory, Nippon Steel Corporation, 1 Kimitsu, Kimitsu, 299-1141 Japan. E-mail: kawata.hiroyuki@nsc.co.jp 4) Department of Materials Science and Engineering, Kyushu University, 744 Motooka, Nishiku, Fukuoka, 819-0395 Japan. E-mail: kaneko@zaiko.kyushu-u.ac.jp (Received on December 21, 2011; accepted on February 27, 2012 ) In this study, three different microstructures of dual-phase (DP) steel obtained by varying the intercritical annealing temperature were observed three dimensionally by a serial-sectioning method and their metrics and topological properties were quantified. The results demonstrated that martensite in DP steels has var- ious morphologies such as layers, particles, holes, and voids. The fraction of these characteristic morphol- ogies was examined as a function of the intercritical annealing temperature. KEY WORDS: dual-phase steel; morphology; topology; 3D; serial-sectioning method. logical assessment has been used to evaluate the dispersivity 1. Introduction