Paper Title:

Grain Boundary Embrittlement and De-Embrittlement in Age Hardenable Iron Alloys

Periodical Materials Science Forum (Volume 710)
Main Theme Advances in Metallic Materials and Manufacturing Processes for Strategic Sectors
Edited by S.V.S. Narayana Murty
Pages 11-18
DOI 10.4028/www.scientific.net/MSF.710.11
Citation Yoon Uk Heo et al., 2012, Materials Science Forum, 710, 11
Online since January, 2012
Authors Yoon Uk Heo, Hu Chul Lee
Keywords Age Hardening, Embrittlement, Fe-Mn-Ni Alloy, Grain Boundary, Precipitate, Twinning
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Abstract

Grain boundary embrittlement and de-embrittlement observed in age hardening iron alloys were reviewed. Fe-Mn-Ni and Fe-Ni-Ti alloys show excellent hardening response during aging treatment. However these alloys all suffer grain boundary embrittlemnt and show no tensile ductility even after very short aging treatment. Precipitation of intermetallic phases, θ-MnNi in Fe-Mn-Ni alloys and η-Ni3Ti in Fe-Ni-Ti alloys, at grain or lath boundaries was suggested as the reason for the weakening of grain boundary strength. Grain boundary strength recovered when these precipitates transform to austenite after extended aging. Dislocation glide or dislocation climb did critical role in conversion of these grain boundary precipitates to austenite.