Microstructure formation of high pressure torsion processed (α + γ) two phase stainless steel

Mie Ota, Daiki Nanya, Sanjay Kumar Vajpai, Kei Ameyama, Kaveh Edalati, Zenji Horita

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

    1 Citation (Scopus)

    Abstract

    (α + γ) two phase stainless steel (Fe-21%Cr-4.8%Ni-1.5%Mo) powder was processed by high pressure torsion (HPT) and consolidation at room temperature. The received powder had fully α single phase due to the rapid cooling during gas atomizing process. Specimens after HPT process were heat treated at 1173K for 3.6ks. It was revealed that the decomposition of α phase to γ took place during the heat treatment. Detailed microstructure observation showed that an equiaxed (α + γ) micro-duplex structure was developed and its average grain size was approximately 3.2 micrometers. The same heat treatment given to the material without HPT resulted in a coarse two phase microstructure.Therefore, it is considered that an ultra fine grained microstructure was caused by increasing of nucleation sites for γ phase due to severe plastic deformation (SPD) of HPT process. Electron backscatter diffraction patterns (EBSD) analysis indicated that α phase has a {110}/ND strong texture, that is, the α phase seems to have single orientated coarse grain structure. The γ precipitates indicated a {111}/ND strong texture, and the crystallographic orientation relationship of Kurdjumov-Sachs was observed.

    Original languageEnglish
    Title of host publicationTHERMEC 2016
    EditorsChristof Sommitsch, Mihail Ionescu, Brajendra Mishra, Brajendra Mishra, Ernst Kozeschnik, T. Chandra
    PublisherTrans Tech Publications Ltd
    Pages1365-1368
    Number of pages4
    ISBN (Print)9783035711295
    DOIs
    Publication statusPublished - Jan 1 2017
    Event9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016 - Graz, Austria
    Duration: May 29 2016Jun 3 2016

    Publication series

    NameMaterials Science Forum
    Volume879
    ISSN (Print)0255-5476
    ISSN (Electronic)1662-9752

    Other

    Other9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016
    Country/TerritoryAustria
    CityGraz
    Period5/29/166/3/16

    All Science Journal Classification (ASJC) codes

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

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