The investigation of nanostructure formation in intermetallic γ-TiAl alloys

摘要

In given work the problems of nanostructure formation in intermetallic γ-TiAl alloy by niobium doping and using of plastic deformation under non-stationary temperature conditions are studied. This investigation is aimed at the possibility of obtaining in γ-TiAl alloys, the preparation of lamellar microstructures with a small colony size with nanocrystalline interplanar distance. It is established that doping of γ-TiAl alloys with niobium (7-8% by weight) and an increasing of plastic deformation degree in conditions of extrusion at a load of 100 MPa allows to significantly reduce the grain size in the final product (to 10-12 μm) and forms two-level structure with nanolamellar colony with distance up to 500 nm. Calculations, carried out using the Hall-Petch model, have shown that obtained Ti-Al-Nb alloy with lamellae nanostructure has limit strength up to 1800 MPa which in 3 times more than in Ti-Al alloy.