Regulating the Phase Transformations in Magnetically Hard Alloys on Heat Treatment in a Magnetic FieldN. N. PotapovBardin Central Scientific-Research Institute of Ferrous Metallurgy, Moscow

摘要

Magnetically hard alloys are an important group of precision alloys. Their optimal magnetic properties are obtained by complex heat treatment, which leads, as a rule, to the formation of heterogeneous (multiphase) crystalline structures. Such structures arise as a result of phase transitions: atomic ordering, spinodal decomposition, or martensitic transformation. One means of improving the performance of magnetically hard alloys is heat treatment in a magnetic field. Thermomagnetic treatment leads to significant rearrangement of the crystalline structure determining the alloy's magnetic properties. For some alloys--primarily those with spinodal decomposition--the effectiveness of thermomagnetic treatment has been reliably established. Thus, we know that the improvement in magnetic properties on thermomagnetic treatment is associated with texture formation--mainly the formation of phase regions with a specific orientation of their crystallographic axes to the magnetic field [1]. Thermomagnetic treatment of alloys with other types of phase transitions requires further study. On the basis of the physical mechanism of thermomagnetic treatment and adequate models, the influence of the magnetic field on the phase transitions in the alloys may be evaluated. This offers a means of regulating the thermomagnetic treatment of magnetically hard materials.