Samples of Ti-6Al-4V and Timet 550 (Ti-4Al-4Mo-2Sn-0.5wt%Si) were subjected to strain rates of between 10-1 and 103/s, and a detailed transmission electron microscopic examination was made of dislocation structures in the α grains. In samples which had been deformed to a strain of 0.1 at 10-1/s, detailed analysis of the defects could be carried out using all diffraction vectors and the presence of c+a dislocations and a dislocations was confirmed. In samples which had been strained to the same strain (0.1) at 5/s, it was not possible to obtain images of dislocations by using diffraction vectors other than 00▪2. The presence of dislocations which had a Burgers vector that contained a c component could thus be confirmed in samples strained at 5/s, but the presence of a component dislocations could be deduced only from transmission electron microscopy of the samples; because of the difficulty of obtaining images with diffraction vectors other than 00▪2. Some observations of samples which had been strained at 103/s showed that similar difficulties occurred in imaging dislocations; like those for samples deformed at 5/s. However, at the highest strain rate used the difficulties were reduced since the images could be obtained in some grains by using diffraction vectors other than 00▪2.

The Influence of Strain Rate on the Visibility of Dislocations in Transmission Electron Microscopy Images of Deformed Ti-6Al-4wt%V and in Timet 550. M.Zakaria, W.Voice, A.Wilson, M.H.Loretto, X.Wu: Philosophical Magazine, 2004, 84[9], 887-98