Formation and Growth of Titanium Aluminide Layer at the Surface of Titanium Sheets Immersed in Molten Aluminum

In this work, kinetics of intermetallic compounds formation in Al- Ti system was studied by immersing titanium sheets in pure molten aluminum at 750°C, 850 °C and 950°C. According to Scanning Electron Microscopy and X-Ray Diffraction Analysis results, TiAl3 is the only phase can form at the interface. Observations revealed that intermetallic layer thickness increases slowly at primary stages. After that an enhanced growth rate occurs due to layer cracking and disruption. Presumably, reaction starts with solving titanium into the molten aluminum causing in titanium super saturation and TiAl3 formation. At this stage, growth may be controlled by aluminum diffusion through intermetallic layer which consequently leads to TiAl3 formation at the interface of Ti-TiAI3. Furthermore, activation energy of intermetallic layer formation and growth was developed by measuring titanium thickness decreases.