Purpose. This paper is devoted to the study of the effect of quenching from the melt on the features of the formation of metastable states and the physical properties of Co − 23 % Be and Co − 50 % Be alloys (at. %). Methodology. Quenching from a liquid state was carried out by a known technique of splat-quenching. Cooling rate estimated by foil thickness was ~ 106…107 K/s. Cast alloy samples were obtained by Tamman furnace using a copper mold with a gap of D=0,5 mm. In this case, the estimated cooling rate was ~ (2…3)·103 K/s. The X-ray diffraction analysis was carried out with the use of the URS-2.0 X-ray equipment in filtered cobalt Кa-radiation and by DRON-2.0 diffractometer in monochromatic copper radiation. Microhardness was measured on the PMT−3 microhardnessmeter at a load of 50 g with an accuracy of ± 30..50 MPa. Magnetic studies were carried out on a vibration sample magnetometer with a magnetic field of up to 500 kA/m by comparing the signal from a splat-quenched sample with a sample of pure nickel, for which the specific magnetization was precisely determined. The accuracy of determining the period of the crystal lattice of the alloy, taking into account the extrapolation of the reflection angle by 90 0, was ± 3·10–4 nm. Findings. The formation of homogeneous highly supersaturated (up to 23 at. %) solid solutions having the composition of the initial liquid (С0) was revealed in Co − Be alloys by the method of quenching from the liquid state. At the maximum cooling rates (107 K/s), which are sufficient to form a solid amorphous state, it is not possible to prevent ordering processes in the congruent equiatomic phase of Co − Be (type CsCl). Originality. It was experimentally confirmed that under the conditions of quenching from a liquid state a significant supercooling of the melt below the decay temperature of the phases of the eutectoid composition b1 in the Co − Be alloys. The positive role of the QLS method in increasing the level of mechanical and hard-magnetic characteristics in rapidly-quenched films is shown. Practical value. Co-Be alloys in the form of splat-quenched films can be used in modern high-tech materials of microelectronics .