Mechanism of interfacial reaction between Ti and Al-ceramic

• The interfacial phase structures obtained at different temperatures are different.
• The generation of Ti7Al5Si12 changes the “metal/SiC” interface to the “metal/Ti7Al5Si12/SiC” interface.
• The welding temperature should not be set below 600 °C, because Ti7Al5Si12 can not be formed below 600 °C.
• The binding force of the joints is enhanced with the holding time prolonging or the pressure increasing.

The interfacial reaction between Ti and Al-Ceramic was investigated. The diffusion-reaction between Ti and Al-Ceramic was tested under various welding temperatures, holding time and pressures respectively. Moreover, the microstructures of the interface layers under different conditions were analyzed, and the properties and fracture morphology of the joints were examined. The results indicated that the compositions of the interface layers and the mechanisms of the reactions were different in a temperature-dependent way, and the maximum shear strength was 70 MPa. The joints fractured between Ti7Al5Si12 and Al-Ceramic with some Al torn off from Al-Ceramic. In any case, the generation of Ti7Al5Si12 was favorable for the Al-Ceramic welding. Ti7Al5Si12 attached to the surfaces of the SiC particles and changed the “metal/SiC particles interface” to “metal/Ti7Al5Si12/SiC particles interface”, improving the mechanical properties of the joints. However, Ti7Al5Si12 was generated only above 600 °C. If it was welded at 600 °C, the holding time should be longer than 0.5 h, and the mechanical property was improved by prolonging the holding time.

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