Microstructure evaluation during plastic deformation in a centrifugal spray deposition (CSD) Ti-48Al-2Mn-2Nb alloy

The microstructures and properties of Ti-48Al-2Mn-Nb alloy formed by centrifugal spray deposition (CSD) were investigated. Hot isostatic pressing was employed to remove the porosity of CSD samples. The tensile and compressive tests were carried out at ambient temperature and, especially, compression strains of 1, 3, 5, 10 and 20%, respectively, were also done. The results show that the ductility of CSD TiAl alloy is around 3%. On the other hand, an excellent compression behavior is achieved, which shows 2210–2310 MPa of compressive strength and 34–38% of compressive ratio. The scanning electron microscopy observations show that the character of slip bands is related to the lamellar structure of TiAl, which slips along the interfaces between the layers. Transmission electron microscopy observations show lots of twins and some dislocation lines built up in the boundaries between lamellar domains or between the lamellae.