Hot corrosion behaviour of (γ + α2)-Ti-46Al-8Nb (at.%) and α-Ti-6Al-1Mn (at.%) alloys

Hot corrosion behaviour of (gamma + alpha(2))-Ti-46Al-8Nb (at.%) and alpha-Ti-6Al-1 Mn (at.%) alloys was investigated in thermal cyclic conditions at 700, 800 and 900 degrees C. The samples were intentionally contaminated with Na2SO4 or NaCI or with a mixture of these. The corrosion rate was evaluated on the basis of mass change measurements. Degradation of materials was examined at the surface and on cross-sections by scanning electron microscopy (SEM). The chemical and phase composition of scale was determined with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). It has been demonstrated that both (gamma+alpha(2))-Ti-46Al-8Nb (at.%) and alpha-Ti-6Al-1 Mn (at.%) are not resistant to hot corrosion. Remarkable mass changes of samples accompanied by intensive scale spallation was observed especially with sodium chloride deposit. (C) 2016 Elsevier Ltd. All rights reserved.