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An analysis method for the detectability of defects on the TC4 (Ti-6Al-4V) diffusion bonding interface was proposed in this study. First, a semi-analytical model of the liquid–solid coupling acoustic field with attenuation characteristics was constructed. Based on this, a method for the selection of transducer parameters was investigated for effective focus on the diffusion bonding interface. Second, according to the characteristics of defects on the diffusion bonding interface, an acoustic response model for diffusion bonding defects was established based on Kirchhoff approximation. The detectability of defects on the diffusion bonding interface was analyzed using transducers of different frequencies with different diffusion bonding interface gaps. Finally, an experiment was conducted to verify the reliability of the simulation. The analysis method proposed shows the advantages in the selection of suitable parameters for detecting specific diffusion bonding interface gaps, providing theoretical predictions of the detectability of diffusion bonding interface defects.

A novel dual array inspection method for detecting the diffusion bonding defects of superalloy turbine disk has been proposed in this study. The influence of relative position between the planar defect and acoustic source has been analysed, and based on which, the transmission and reception algorithm for the dual array method has been proposed. The time delay law of the dual array transducer for the complex turbine disk structure has been investigated. Finite-difference time-domain theory has been used to establish the numerical model of the dual array method. In the numerical simulations, the novel method has been applied for the superalloy turbine disk specimen with prefabricated defects at the depth of 18.3 m and 28.3 mm. Furthermore, the corresponding experiment has been conducted and verifies the reliability of the simulation. The novel method shows advantages in detecting small diffusion bonding defects in complex structure, assisting the manufacture of superalloy turbine disks, and ensuring the safety of aircrafts.