Density and thermal expansion of the nickel-based superalloy INCONEL 625 in the solid and liquid states
S. Heugenhauser and E. Kashnitz
Density and thermal expansion of the nickel-based superalloy INCONEL 625 were measured in the temperature range 150 °C to 1400 °C using pushrod and piston dilatometry. Commercial pushrod-dilatometers were used for the measurements. The specimens are cooled and heated slowly at controlled rates in a furnace; the expansion is transferred by a long thin rod to displacement sensors. In the high temperature range an alumina tubular body with two alumina pistons of just sufficient clearance was used to contain the specimen in the mushy region and in the liquid state
The investigated material was primary heat treated at 930 °C for 1 hour. As INCONEL 625 is an age-hardening alloy, the thermophysical properties including density at elevated temperature depend slightly on heat treatment conditions. Therefore, different measurement runs with a variation of the maximum temperature in the solid state (from room temperature to 1000 °C, 1100 °C and 1250 °C) were performed to cover different heat treatments (product grades) of INCONEL 625.
Due to the lack of density and thermal expansion data of INCONEL 625 in the solid and liquid states in the literature, the measured density is compared to published density data of INCONEL 718 and INCONEL 738. A detailed uncertainty analysis of the measured data in the solid and liquid state of the alloy is provided.
Keywords: density; INCONEL 625; liquid metal; nickel-based superalloy; piston dilatometry; pushrod dilatometry; thermal expansion