Viscosity and volume properties of the Al-Cu melts

N Konstantinova,A Kurochkin,P Popel

doi:10.1051/epjconf/20111501024

N Konstantinova, A Kurochkin + Show 1 more

Open Access

https://doi.org/10.1051/epjconf/20111501024

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Abstract

Temperature dependences of the kinematic viscosity v and the density ρ of Al-Cu melts were investigated in the same regime taking into account that viscometric experiments with the melts enriched with cupper have not been repeated since 1960th and densimetric measurements did not perform before at all. The first measurements were fulfilled using the method of dumping oscillation of a crucible filled in by a melt investigated. Its precision was as high as 1.5%. Density was measured using the gamma-absorption method with the accuracy of 0.2 to 0.3%. Crucibles of BeO were used in both the cases. In the course of the measurements a distinct branching of the heating and cooling curves were fixed below some temperature characteristic of each composition for most of the investigated samples. The branching temperature systematically changes with growth of cupper content. The authors believe that the effect is caused by the irreversible transition of the melts from microheterogeneous state inherited from the initial rough materials into a true solution state.

Highlights

Copper-aluminum and aluminumcopper alloys find extensive applications in various fields of engineering
The measurements were conducted at heating and subsequent cooling with the aim of finding signs of their irreversible transition from metastable microheterogeneous state into a thermodynamically stable state of a homogeneous solution
At heating the temperature dependence of density in liquid state is different from the cooling curve at temperatures below 750°C for the eutectic melt containing 17 at.% Cu and at the temperature below 800°C for the melt containing 23 at.% Cu, that is, we observe the phenomenon of density hysteresis

Summary

Introduction

Copper-aluminum (aluminum bronzes) and aluminumcopper (duralumins) alloys find extensive applications in various fields of engineering Their physical properties (electrical and thermal conductivity, mechanical properties, corrosion resistance, and so on) are largely defined by the correlation of concentrations of basic components. EPJ Web of Conferences heating and subsequent cooling They revealed very non trivial features on the (t) curves, indicative of the possibility of reversible or irreversible (depending on the copper content) structure transformations in the investigated melts. That is why in the present study, we measured the temperature dependences of kinematic viscosity of CuAl melts containing from zero to 100% of the second component and the temperature dependences of density for some Al-Cu melts in the mode of heating and subsequent cooling of samples between liquidus and t= 1150-1450°C

Viscosity measurements

Density measurements

Results of the viscometric experiments

Results of the densimetric experiments

Discussion