8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P9.41On mechanism of the nonmonotonic relaxationprocesses in nonequilibrium AL-TM-REM meltsSvetlana Menshikova, 1 Vladimir Ladyanov, 2 Anatolii Beltyukov, 2 and MikhailVasin 21 Udmurt State University, 1 Universitetskaya Str. , 426034, Izhevsk, Russian Federation2 Physical-Technical Institute of the Ural Branch of the Russian Academy of Sciences,Izhevsk, Russian FederationIn the present paper the measuring of the temperature and time dependences of kinematic viscosityof liquid Al-TM-REM alloys was carried out by the method of damped torsional vibrations. Anirreversible non-monotonic change of the melts viscosity above the temperature of melting broughtabout by the destruction of their microheterogeneous state inherited from the multi-phase solidsample has been found out. It is shown that for the melts transition into the quasi-equilibriumstate long isothermal holding is necessary. At the temperatures close to the melting temperaturethe relaxation times are order of 300 minutes. The relaxation time decreases with increase ofthe melt temperature. On the basis of the conception about of a micronon-uniform structure ofmelts in view of the ultrametric dynamic theory of a molecular field the model of a nonmonotonicrelaxation of the nonequilibrium melts has been offered. According to the offered approach, thekey parameter, which influences viscosity, is the concentration of nonequilibrium microgroups ofatoms. In the beginning of isothermal holding of melt the size of these microgroups is great enough,but their concentration is small and does not render essential influence on viscosity. Eventually theconcentration of these microgroups is changing. That is determined by two processes: dissolutionthe largest and dispersion the finest of microgroups. The first process (that is dissolution) leads toincrease in concentration of nonequilibrium microgroups in melt, the second (that is dispersion)leads to reduction of their total. Joint influence of these two processes is shown in nonmonotonicchange of viscosity investigated melts.41