A theoretical model of amorphous phase formation during the quenching of a metal melt is proposed. As shown, the appearance of a significant temperature gradient during the quenching of a metal melt leads to thermodiffusion of defects and their outflow from the melt volume, which manifests itself in a significant reduction in the number of free spaces for the diffusion transfer of atoms of the melt. Due to the thermodiffusion process, a significant transformation of the medium microstructure occurs, which leads to a significant increase in viscosity, a decrease in the diffusion coefficient and specific volume of the substance, and changes in the mechanisms of deformation. Corresponding calculations of temperature distribution, thermodiffusion and distribution of the components of the melt are carried out.