Measurement of the volumetric expansion and bulk density of metals in the solid and molten regions

Over the past few decades, the metals industry has increased its efforts to raise product quality and improve production processes. In particular, the casting process and mould design have been continuously improved. High-speed computers and finite-element casting simulations are widely used to improve control and understanding of the solidification process of metals. The quality of the numerical simulations is strongly dependent on the accurate knowledge of the thermophysical properties of the metals. Thermophysical properties, such as thermal conductivity, thermal diffusivity, specific heat or density change in the solid, liquid, or mushy zones, being critical parameters for the accurate simulation of such casting processes, must be known. The topic of this work is to introduce a new method for measurement of the volumetric expansion and density change in the solid, liquid, and mushy regions by the use of a standard pushrod dilatometer. The new method was tested on copper and iron. Additionally, measurements were carried out on an aluminium alloy, LM-25, and a nickel-based superalloy, Inconel 718.