Microstructure of Ti/Al multilayer foils ignited with electric current

Abstract

Abstract Magnetron sputtered Ti/Al freestanding multilayer foils were treated with an electric current pulse of 0.5 A or 4 A for ∼1 s in order to initiate a self-sustaining high-temperature synthesis. Scanning electron microscopy observations showed that the sample treated with 0.5 A is characterized by the presence of periodic rippled bands, while the 4 A one has a nearly unaffected shape. Transmission electron microscopy experiments revealed that the microstructure of Ti/Al foil ignited with 0.5 A consists of large equiaxed grains of γ-TiAl phase and alternating plates of γ-TiAl + α2-Ti3Al phases, carrying vestiges of their initial multilayer character, while the 4 A treatment resulted in the formation of a duplex microstructure.