Exploring the role of liquid braze filling the dissimilar C_f/C-Haynes 230 joint to enhance the interfacial heat transfer

Traditional thermal interface materials improve heat transfer by increasing the contact area between the heat source and the heat sink. Still, it is only physical contact and has poor thermal conductivity. Filling the interfacial gap of dissimilar solid materials through liquid braze is an effective way to solve the thermal failure caused by excessive interfacial contact thermal resistance. The AgCu4.5Ti alloy is one of the most widely used Ag-based active braze, which can fully wet the C_f/C composite and Haynes 230 alloy to eliminate the interfacial gap and realise interfacial metallurgical joining. In this study, the effects of brazing temperature and holding time on the thermal conductivity of the C_f/C-Haynes 230 joint are investigated systematically. The thermal conductivity of the joints at service temperatures ranging from 25 °C to 600 °C is explored. Results reveal that the joint brazed at 880 °C for 10 min obtained the optimal heat transfer, which reaches up to 23.9 W·m⁻¹·K⁻¹ at room temperature. Whereas at a service temperature of 600 °C, the thermal conductivity of the joint reaches 48.8 W·m⁻¹·K⁻¹. This study provides an important reference for obtaining high thermal conductivity brazed joints.