Electron microscope studies of phase transformations in rapidly solidified MnBi alloys

Abstract

As-made MnBi ribbons produced by the melt-spinning method are amorphous, as shown by X-ray diffraction and TEM studies. The subsequent transformations (induced by heat treatment) involve complex processes. The amorphous phase crystallizes first into Mn 3Bi, Bi and ferrimagnetic MnBi (NP). The formation of the low-temperature MnBi phase (LTP) immediately follows the melting of the Bi phase. It is possible to obtain the LTP in the amount exceeding 95 wt.%. At higher temperature, transformation of the LTP into the high-temperature MnBi phase (HTP) occurs.