Fig. 1. Schematic of the ultrasonic-assisted brazing process.

Fig. 2. Schematic of: (a) segmentation of the joint sample; (b) specimen used in the shear test; (c) custom designed fixture for the shear test.

Fig. 3. Microstructure and XRD analysis of the as-received materials: (a) and (a-1) SiC ceramic; (b) and (b-1) A-12Si alloy.

Fig. 4. Microstructure and fracture behavior of the joint for an ultrasonic time of 4 s: (a) whole joint; (b) interface; (c) fracture path in the joint; (d) fracture surface and the local magnification.

Fig. 5. Change of the joint shear strength with a varying ultrasonic time.

Fig. 6. Microstructure of the interface of the joint for an ultrasonic time of 16 s in HRTEM: (a) bright-field image and SAED patterns of phases around the interface; (b) HRTEM image of interfacial area with a partial amorphous phase; (c) HRTEM image of interfacial area with a continuous amorphous layer.

Fig. 7. XPS analysis of the surface of SiC ceramic after thermal treatment (620 °C): (a) typical XPS survey spectra; (b) XPS spectra of the Si2p core level region.

Fig. 8. Microstructure of the interface between Al-12Si and SiCox (1100 °C, 6 h) for an ultrasonic time of 8 s: (a) backscattered electron image; (b) bright-field image and local-amplification image; (c) HRTEM image and SAED patterns of interfacial amorphous layer; (d) HRTEM image and SAED patterns of interfacial reaction product.