Crystallographic orientation variation of isothermal pearlite under high magnetic field

Abstract

Crystallographic orientation (CO) variation of magnetic-induced pearlite (MIP) during its microstructure evolution in 19.8T was investigated by electron back-scatter diffraction (EBSD). It is closely related to the isothermal temperatures (ITs) and the applied magnetic time (MT) during the process of MIP formation. The <100> easy magnetization direction in MIP colonies is strengthened with the MT within the certain transformed fraction of MIP (fMIP) at the relatively lower IT (983K) above the eutectoid temperature but below the magnetically shifted upward eutectoid temperature, while this special CO tends to be weakened at a relatively higher IT (995K). For the same MT, the higher the IT, the relatively larger is the proportion in <100> orientation for MIP colonies at the early growth stage. These results have demonstrated that the change of <100> orientation of MIP is closely related to the growth rate of pearlite ferrite (PF), and strengthened mainly at early transformation stage. When fMIP reaches some value, the growth rate of MIP at other COs, such as <110>, even at the hard magnetization direction, turns to present speed-up.