Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 25: Poster Session

MM 25.12: Poster

Wednesday, March 29, 2006, 15:30–17:30, P4

The influence of doping with Ni on viscosity of liquid Al — •Andriy Yakymovych, Stepan Mudry, Vasyl Sklyarchuk, and Volodymyr Halchak — Physics of Metals Department, Ivan Franko Lviv National University,Kyrylo I Mephodiy Str. 8, 79005, Lviv, Ukraine

The addition of Ni to aluminium allows to improve its physical-chemical properties, which are important for practical use. It is interesting to clarify how change the main properties of Al in liquid state upon doping. On that, reason the viscosity of Al-Ni molten alloys with 2.5, 5, 7.5 at.% of Ni has been studied in this work by means of oscillating crucible method. Analyzing the available data on viscosity of Al and Al-based alloys one can conclude that there is a discrepancy between them.

Temperature dependence of viscosity coefficient for melts of various Al content shows Arrhenius like shape. With addition of Ni-atoms to aluminium the viscosity coefficient increases. The experimental data were compared with ones calculated for hard sphere model.

It is shown that chemical atomic ordering which is more pronounced for higher content of Ni may be the main reason of observed viscosity and activation energy change. We suggest that due to preferred interaction of Al and Ni atoms associates are responsible for the viscosity changes of neareutectic molten alloys. The content of Al and Ni in such chemically ordered structural units can vary in some wide range. This range is supposed to be significantly wider than homogeneity range for solid AlNi compound.