EN
In alloy materials, the onset of crystallization temperature (T_{x}) is treated as the threshold of structural stability. In amorphous materials, this threshold is the temperature above which heterogeneous crystalline grains begin to appear. However, in amorphous materials, frozen nuclei of the crystalline grains also come into existence during the production process. These nuclei have a strong influence on the properties of the amorphous materials. The growth of the nuclei of the crystalline grains is possible even below the crystallization temperature, and maintaining control over their size allows the application properties, for example the magnetic properties, to be controlled. In this paper, the influence of two-stage isothermal annealing (below the crystallization temperature) on the structure and magnetic properties of Fe_{61}Co_{10}Y_{8}W_{1}B_{20} alloy was investigated. Samples of the material were prepared in the form of plates, and subjected to thermal treatment at temperatures of 700 K and 770 K, for 1 and 3.5 hours, respectively.