The measurement and estimation of density for selected liquid alloys
P. Quested, R. Morrell, A. Dinsdale and L. Chapman
The simulation modelling of metal processes requires realistic, accurate and self-consistent thermophysical properties as input data. In particular, solidification models have been shown to be sensitive to small changes in the density of the liquid alloy. This paper compiles experimental data for the density of selected liquid aluminium, magnesium and nickelbase alloys at their liquidus temperatures. These data are drawn from the published literature and some of our own previously unpublished results.
Comparison with ideal mixing calculations for the selected aluminium and magnesium alloys shows reasonable agreement between the calculations and the experimental results within the experimental measurement uncertainties. For aluminium alloys, the composition limits in Cu; Ni and Ag additions required to produce a 1% deviation from ideal behaviour are calculated allowing for the binary interactions between these elements and aluminium.
For a selection of nickel based super alloys the ideal model predicts lower densities than the experimental measured values. These differences are interpreted mainly in terms of the published experimental non-ideality of mixing of the Ni-Al system and to a lesser extent reported binary interactions for other systems. Correction for these effects results in significantly improved agreement between the density predicted by the non-ideal model and experimental values.
Keywords: density, liquid, aluminium alloys, nickel alloys, magnesium alloys, measurement, estimation