Effect of Ti Particles on Microstructural Evolution and Mechanical Properties of Ultrasonic‐Assisted Al ₂ O ₃ Ceramic/Zn5Al‐xCu/2024Al Solder Joints

Al 2 O 3 ceramics and 2024Al are advanced engineering materials with excellent properties and wide‐ranging applications in fields such as electronic packaging and aerospace. However, due to the significant difference in the coefficient of thermal expansion (CTE) between the two materials, stress is inevitable and may result in insufficient joint strength. In this study, the Zn5Al eutectic alloy is modified by incorporating the Cu element to address this interfacial mismatch issue. The Cu undergoes a reaction with the Zn present in the solder, resulting in the formation of the brittle CuZn 5 . The even dispersion of the CuZn 5 phase in the solder results in a reduction of its CTE, alleviating the residual stresses in the soldered joint. To further enhance the joint strength, Ti particles are employed as reinforcement to improve the mechanical behaviors of the solder. The results indicate that using Zn5Al2Cu solder achieves a mean shear strength of 84.80 MPa for the soldered joints, which is 115% higher than that of the Zn5Al solder. Additionally, when Zn5Al2Cu‐5Ti p composite solder is used, the mean shear strength of the soldered joints can further reach 113.00 MPa, promoting the application of this soldered joint in the field of high strength and high reliability.