| 摘 要： | Ultrasonic-assisted brazing of SiC ceramics was performed by filling with an Al—12Si alloy at a low temperature of 620 °C in air. The interfacial characteristics and formation mechanism were investigated. The joint shear strength reached 84–94 MPa using the ultrasonic time of 2–16 s. The fracture morphology showed that the fracture path initiated and propagated in the joint alloy. The thin film of amorphous SiO 2 that formed on the SiC surface was non-uniformly decomposed and diffused into the liquid Al—12Si alloy under the cavitation erosion effect of ultrasound. Abnormal isolated blocks of Al_2 SiO_5 compounds formed at the interface between Al—12Si and a thicker SiO_2 layer formed during the thermal oxidation treatment of the Si C ceramic. The SiO_2 layer on the Si C ceramic did not hinder or impair the wetting and bonding process, and a stronger bond could form between Al—12Si and SiO_2 or Si C in ultrasonicassisted brazing.
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