Magnetic evaluation of the hardening and softening of thermally aged iron–copper alloys

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Abstract

We evaluated the variations of the magnetic hysteretic behaviour of Fe–1wt%Cu model alloy samples due to thermal aging and over-aging. In these alloys, the formation and growth of Cu-precipitates during the thermal aging process results in mechanical hardening, whereas for aging times higher than a certain critical value, mechanical softening occurs. Magnetic hysteretic properties such as permeability, remanence, peak value and width of the local interaction field distribution, which is related to the Preisach model, are measured as a function of various Cu-precipitation stages obtained by time dependent heat treatments at 773K (500 ◦C).We found that all magnetic parameters exhibit an extremum value for the peak hardening sample. Furthermore, the variation of permeability, remanence, and the peak value of the local interaction field distribution mimics the behaviour of the reciprocal value of the yield stress as a function of aging time. These results suggest that the magnetic domain wall movement is hindered mainly by Cu-precipitates upon thermal aging. The peak hardening values of the investigated magnetic parameters change by approximately 50% when compared with the initial values. This pronounced sensitivity indicates the potential of magnetic non-destructive evaluation for the assessment of the hardening and softening phenomena induced by Cu-precipitation.

Details

Original languageEnglish
Pages (from-to)4114-4119
JournalJournal of Physics D: Applied Physics
Volume40
Issue number14
DOIs
Publication statusPublished - Jun 2007

Keywords

  • magnetisation, sofftening, Fe-Cu alloy

ID: 192558