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Thermophysical properties of nickel-based single crystal of Rene′ N5
Daeho Kim, Jaeyoung Park, Seung Hoon Nahm and Sanghyun Lee

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 Rene′ N5 alloy in a temperature range of room temperature to 1000 °C. Especially, specimens of Rene′ 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, Rene′ N5 and conventional cast Rene′ 80 of reference data. The microstructures of alloys [001] and [111] of Rene′ N5 were observed by SEM and found to have phase of γ/γ‘, which affects the thermophysical properties.

Keywords: Rene′ N5, Thermal diffusivity, Specific heat capacity, Thermal conductivity, Coefficient of thermal expansion