Formation of ultrafine grained ferrite by warm deformation of tempered lath martensite in low alloy steels

B. Poorganji, T. Yamaguchi, T. Maki, G. Miyamoto, T. Furuhara

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Citations (Scopus)

Abstract

Microstructure change during warm deformation of tempered lath martensite in Fe-2mass%Mn-C alloys with different carbon contents in the range between 0.1 and 0.8mass%C was investigated. Specimens of the alloys after being quenched and tempered at 923K for 0.3ks were compressed by 50% with a strain rate varying from 10-3 to 10"V at 923K. EBSD analysis of the deformed microstructures has revealed that fine equiaxed ferrite (a) grains surrounded by high-angle boundaries are formed by dynamic recrystallization (DRX). As carbon content increases, the DRX a grain size decreases. This could be attributed to the change in volume fraction of the cementite (6) phase as boundary dragging particles. The sub-micron 9 particles can suppress the coarsening of the DRX a grains by exerting a pinning effect on grain boundary migration. Furthermore, the fraction of recrystallized region increases by increasing carbon content, presumably due to a decrease in the martensite block width as an initial a grain size and a larger volume fraction of hard second phase (6) particles. Both of these should increase inhomogeneous plastic deformation which promotes the recrystallization. It seems that continuous DRX is responsible for the formation of ultrafine a grains in the tempered lath martensite.

Original languageEnglish
Title of host publicationRecrystallization and Grain Growth III - Proceedings of the Third International Conference on Recrystallization and Grain Growth, ReX and GG III
PublisherTrans Tech Publications Ltd
Pages557-562
Number of pages6
EditionPART 1
ISBN (Print)087849443X, 9780878494439
DOIs
Publication statusPublished - 2007 Jan 1
Event3rd International Conference on Recrystallization and Grain Growth, ReX GG III - Jeju Island, Korea, Republic of
Duration: 2007 Jun 102007 Jun 15

Publication series

NameMaterials Science Forum
NumberPART 1
Volume558-559
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752

Other

Other3rd International Conference on Recrystallization and Grain Growth, ReX GG III
CountryKorea, Republic of
CityJeju Island
Period07/6/1007/6/15

Keywords

  • Dynamic recrystallization
  • Lath martensite
  • Ultrafine grain
  • Warm deformation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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