Characteristics of laser metal deposited titanium aluminide

The unique properties of titanium and its alloys make them a continuous area of interest for the material researchers and high profile material industries. Titanium and its alloys possess high strength-to-weight ratio and excellent corrosion resistance properties which made them very useful for high temperature applications especially in areas such as energy generation, automobile and aeronautic industries. In this paper, the effect of deposition parameters on the properties of laser fabricated titanium aluminide alloy was studied. Titanium aluminide powder (Ti-4822-4) was deposited on pure titanium substrate using laser engineered net shaping (LENS) technique of additive manufacturing. Processing parameters like the laser power, scanning speed and powder flow rate were varied. Laser power was varied between 300 to 500 W, scanning speed varied between 3.174 to 7.406mms^-1 and powder flow rate varied between 4.09 to 7.12 g min^-1. The design and analysis of the results was carried out using design expert 6.0.8 software. The trends in deposits cracks, heights and microhardness in relation to the deposition parameters have been studied. The outcome of the study showed that cracks in the deposits reduced as the laser power increases and scanning speed reduces. It was also revealed that the overall microhardness increases as the laser power, scanning speed and powder flow rate increases. The height of the deposits increases as the laser power increases, scanning speed decreases and powder flow rate increases. Microscopic images of the deposits revealed massive presence of γ-TiAl and isolated lamellar region of γ-TiAl and Ti3Al.