Structure of the Fe63.5Ni10Cu1Nb3Si13.5B9 Alloy Nanocrystallized in the Presence of Tensile Stresses

Resumo

The structure of the Fe_63.5Ni₁₀Cu₁Nb₃Si_13.5B₉ alloy, which is a classic alloy of the FINEMET type with 10 at % Ni substituted for Fe, has been studied after crystallization in the presence of tensile stresses. It has been shown that, upon the crystallization of the alloy (520°C) both in the presence of a tensile load and without it, nanocrystals of an α-(Fe, Ni)Si solid solution and of the Fe₃Si phase are formed with an increase in the duration of annealing from 10 min to 1 hour. When the length of the annealing is further increased from 1 to 4 hours, a tetragonal phase Fe₃NiSi_1.5 appears in the alloy. A relationship between the structural state (phase composition) of the Fe_63.5Ni₁₀Cu₁Nb₃Si_13.5B₉ alloy and its magnetic properties and the type of the induced magnetic anisotropy has been shown. The growth of the coercive force, which was previously observed in samples of this alloy as the duration of the annealing was increased to 4 hours, is therefore associated with the appearance of a tetragonal phase in the alloy. The transverse magnetic anisotropy, which is induced in the alloy in the process of nanocrystallizing annealing in the presence of a tensile load, is associated with the formation of nanocrystals of the α-(Fe, Ni)Si solid solution and of the Fe₃Si phase with a negative magnetostriction.