On distribution of impurities in titanium alloys

A fracture surfaces of the VT-22 alloy are investigated by the Auger spectroscopy method in order to determine a composition and distribution of impurities in samples cast and annealed at 750 deg C. Segregation of carbon, oxygen, sulphur, chlorine, sodium, vanadium and aluminium are discovered on a fracture surface occurring along an initial β-grain boundaries. Annealing leads to redistribution of impurities and decrease of their content on grain boundaries. It is shown that presence of impurities in solid solution and along grain boundaries, which can not be controlled in line with production process, leads to a decrease of alloy ductilily and to instability of their properties