Interfacial characterization using transmission electron microscopy examination of the diffusion bonding of SiC whisker-reinforced aluminum alloys

This paper describes the microstructural characterization, using transmissi on electron microscopy (TEM), of the solid-state, diffusion-bonded interfac es generated in a SiC whisker-reinforced, aluminum composite. Diffusion bon ding was carried out using an aluminum-lithium alloy as the bonding interla yer. Two kinds of bonded interface were studied: those generated between th e composite matrix and the metallic interlayer (metallic-metallic) and othe r ceramic-metallic interfaces formed between the interlayer and the SiC whi skers. The first showed the formation of zones of recrystallization across the original bond interface, and the second generally presented a high degr ee of continuity without the formation of interface reaction layers between the SiC whiskers and the interlayer, However, the formation of a degradati on oxide layer was detected in some of the whisker/interlayer diffusion bon ds. Its presence is due to the reaction between the alloying elements of th e AI-Li interlayer and the SiO2 layer which surround some of the whiskers o f the parent composite.