Effect of high magnetic field on phase and structural transformations in ferromagnetic alloys. Review

Review of relevant research about the effect of high DC magnetic field on structural and phase transformations in different ferromagnetic alloys are presented. Main experimental results of simultaneous impact high temperature and magnetic field with induction up to 45 T on alloys Fe-C, Fe-Co, Fe-Si, Mn-Bi, Fe-Ni, Ni-Co and other are presented. The main high magnetic field effect on a phase transformation is equilibrium temperature changing, which reaches tens degrees. Modern views about cause of such effect, which consist in changing of thermodynamic conditions of transformation under external magnetic field due different magnetic properties between parent and appearing phase are described. In the theoretical and experimental determination of the phase transformation temperature shift magnitude in most cases there is a significant discrepancy. The probable causes such discrepancy are discussed. Moreover, review of results on investigations effect of magnetic field on structure transformations; in particular recovery and recrystallization in cold-rolled ferromagnetic alloys are presented. It is shown, that magnetic field retards recovery process and furthermore promotes preferential formation of certain texture components. Nowadays there is no consensus in the scientific literature on the nature of the observed effects. In this paper, critical analyses of the approaches proposed by different authors to the interpretation of experimental results are presented. The current state of the problem is described; in conclusion, the prospects for further studies of thermally activated processes in the conditions of application of a high DC magnetic field are indicated.