Thermomagnetic characterization in AISI 316L austenitic stainless steel fibers with various true strains

This paper investigated the effect of temperature on the magnetic properties of AISI 316L stainless steel wire drawn to micron-size fibers with various true strains using thermomagnetic analysis (TMA). The volume fraction of martensite induced by deformation was determined using a superconducting quantum interference device and a Ferritescope. During the heating process, the content of alpha' martensite in the samples with a true strain of above 2.31 increased at around 460 degrees C. A shoulder of reverse transformation from alpha' to gamma was observed at around 625 degrees C in the TMA heating curves for samples with a true strain above 1.61. The shoulder shifted slightly to a higher temperature as the true strain increased. The relatively small increase in magnetization above approximately 760 degrees C was related to the ferrite content, as confirmed by electron probe microanalysis-wavelength-dispersive spectrometry. During the cooling process, the M-s temperature decreased as the true strain of fibers increased. (C) 2012 Elsevier B.V. All rights reserved.