Characterization of strain-induced martensitic transformation in A301 stainless steel by Barkhausen noise measurement

Kinetics of strain-induced martensitic transformation under biaxial stress state in metastable austenitic AISI 301 stainless steel was characterized by electron back-scattered diffraction and Barkhausen noise measurement. The effect of martensite volume fraction, degree of plastic strain, crystallographic texture and stress state on magnetic properties was evaluated. Increase in Barkhausen noise signal is related both to an increase in the magnetic domains volume fraction due to a transformation of non-magnetic austenite to magnetic martensite and to a reorientation of magnetic domains into 〈1 0 0〉 direction. Up to the saturation of martensite volume fraction, Barkhausen noise is affected by newly created martensite, and subsequently by plastic strain. The intensity of Barkhausen noise signal is strongly angle-dependent as the easy magnetization axis is developed in the transverse direction of pre-strained sheets.