Attention was focussed here on the effect of various microstructures, obtained by heat-treatment, upon the diffusion coefficient and mechanical properties following H absorption. Modification of γ-TiAl could be achieved by heating as-cast binary samples of Ti–45%Al to 1200C and cooling in 3 different ways (quenching, air-cooling, furnace-cooling). All of the samples were then subjected to corrosion attack under cathodic charging, in the galvanostatic mode, for 6h. The potential variation with time was monitored. From these data, the diffusion coefficient of H in γ-TiAl was calculated on the basis of Fick’s second law. This result was compared with that obtained by micro-Vickers hardness profiling from the top corroded surface. Hydrides which formed at the surface were analysed by using image analysis, scanning electron microscopy and X-ray diffraction. The results showed that differing microstructures had an effect upon the diffusion coefficient and mechanical properties following H absorption.             

Effect of Heat Treatment on the Diffusion Coefficient of Hydrogen Absorption in Gamma-Titanium Aluminide. K.Suardi, E.Hamzah, A.Ourdjini, V.C.Venkatesh: Journal of Materials Processing Technology, 2007, 185[1-3], 106-12