The use of Barkhausen noise to study the martensitic phase transformation

Edgar Apaza Huallpa, Paula F.S. Farina, Julio Capo, Linilson R. Padovese, Hélio Goldenstein

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

The use of magnetic Barkhausen (MBN) noise methods to detect the austenite to martensite phase transformation during cooling of steel specimens was explored, using three different configurations: conventional Barkhausen noise emission stimulated by an alternating magnetic field, the Okamura method, that measures magnetic noise emission under a fixed DC field and a novel experimental technique that measures spontaneous magnetic emission during transformation, in the absence of any external field. The phenomena associated with the phase transformation were also followed by electrical resistivity measurements and the resulting samples were characterized using optical and scanning electron microscopy. MBN measurements on a AISI D2 tool steel austenitized at 1473K and cooled to liquid nitrogen temperature exhibited a clear change near 225 K during cooling, corresponding to the Ms (martensite start ) temperature, as confirmed by resistivity measurements. Spontaneous magnetic noise emission measurements made in situ during cooling of a sample immerged in liquid nitrogen showed that individual "burst" phenomena could be detected, in a manner similar to acoustic emission (AE) measurements. This magnetic emission (ME) can thus be considered a new experimental tool for the study of martensite transformations in ferrous alloys.

Original languageEnglish
Title of host publicationSolid-Solid Phase Transformations in Inorganic Materials
PublisherTrans Tech Publications Ltd
Pages184-189
Number of pages6
ISBN (Print)9783037851432
DOIs
StatePublished - 2011
Externally publishedYes

Publication series

NameSolid State Phenomena
Volume172-174
ISSN (Print)1012-0394

Keywords

  • Barkhausen noise emission
  • Cryogenic treatment
  • Magnetic emission
  • Martensitic transformation

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