Thermophysical properties of nickel-based single crystal of René N5

Abstract

Nickel-based superalloys have been widely used for various high-temperature and high-pressure applications such as gas-turbines, power plants, and boiler housings. In this study, we report new experimental results for thermophysical properties of René N5 alloy in a temperature range of room temperature to 1000 °C. Especially, specimens of René N5 alloy were studied in directions [001] and [111] from the same batch of commercial alloy bar. Thermal diffusivity, specific heat capacity, thermal conductivity, and coefficient of thermal expansion (CTE) with correction data of density were evaluated for each measurement method, and detailed data are provided in tables. Thermal conductivity of the [001] alloy had a higher trend than that of the [111] alloy, with relative deviation of 0.7% to 4.8%. Coefficient of thermal expansion values showed good agreement (within 5.3%) and had a curve similar to that of the specific heat capacity. All thermophysical property results were described and compared with those of single crystal alloy of CMSX-4, René N5 and conventional cast René 80 of reference data. The microstructures of alloys [001] and [111] of René N5 were observed by SEM and found to have phase of γ/γ′, which affects the thermophysical properties.