Reactive wetting of Ti-6Al-4V alloy by molten Al 4043 and 6061 alloys at 600–700°C

Abstract

Abstract Wetting of Ti-6Al-4V alloy by two industrial grade Al alloys (i. e., Al 6061 and 4043 alloys) was studied using the sessile drop method at 600–700 °C under high vacuum. Al/Ti-6Al-4V is a typical reactive wetting system with good final wettability accompanied by the formation of precursor film which is actually an extended reaction layer. The formation mechanism for the precursor film is “subcutaneous infiltration”. The small amount of alloying element Si in the alloys can cause significant segregation at the liquid/solid interface which satisfies the thermodynamic condition. The wetting behavior can be described by the classic reaction product control models, and Ti7Al5Si12 decomposition and Al3Ti formation correspond to the two spreading stages. The small difference in alloying elements in Al 6061 and 4043 resulted in distinctly different interface structures, formation of precursor film and spreading dynamics, especially for the Si segregation at the interface.