The structure and properties of liquid Ni-Al alloys in a wide range of temperatures have been studied. Analysis of the temperature dependences of the physical and chemical properties of studied alloys discovered the phenomenon of hysteresis, i.e. discrepancy of heating and cooling politerm. This temperature is named hysteresis temperature. On the base of the quasichemical version of nonequilibrium melts structure offered a physical model of the structure of Ni-Al alloys. It is expected that after the melting liquid metal is in equilibrium state. It has as microgroups of NixAl type with strong Ni-Al bond and GCC-like structuremicrogroups with more weaker bonds Ni-Ni. When the melt heated above liquidus temperature the size and lifetime of the cluster decreased. When the melt heated above critical temE peratures clusters on NixAl type disappeared. Melt goes from micrononequilibrium to equilibrium state.