The effect of pressure on thermal contact conductance of superalloys under high temperature

Superalloys GH4169 and K417 are widely used to manufacture components in the hot end of aero-engines due to their excellent mechanical and casting properties, and the thermal contact conductance (TCC) between the two metals is an investigation of interest. The experimental procedure tested TCC between GH4169/K417 interfaces under high temperature of 600 °C using compensation heating technique, and the optimal size of the compensation heater was determined by finite element analysis. A constrained optimization problem is constructed to determine the temperature at the interface, taking into consideration the temperature-dependent thermal conductivity of test specimens. The results show that TCC is almost directly proportional to interface pressure, which is not consistent with results that have been reported. To explain the linear relationship between TCC and interface pressure, a mathematical model based on contact mechanics is built.