Adiabatic Shear Bands in Ti-6Al-4V Alloy with Lamellar Microstructure

Adiabatic shear band (ASB) is an important material’s phenomenon often observed in metals when processed at high strain rates. The microstructure and microtexture of ASBs in Ti-6Al-4V alloy with lamellar microstructure deformed by the dynamic loads were investigated by means of Light Microscope, Scanning Electron Microscopy/Electron Back-Scattered Diffraction, and Transmission Electron Microscopy. Close to the boundary of the shear band, highly elongated subgrains with thick cell walls were observed. The core of ASB consists of very fine equiaxed grains with low density of dislocations. New phases are generated in the core of shear band. According to the orientation distribution, the textures in the core of ASB peaked at (45°,5°, 0°), (89°,29°, 0°), (15°,10°, 30°), and (75°,5°, 30°); and the grain boundaries in ASB are geometrical necessary boundaries with high angles. Calculations of temperature rise suggest that the temperature in ASB is above the recrystallization point. Finally, the formation of an ASB in the Ti-6Al-4V alloy and its microstructure evolution are described as a consequence of the rotational dynamic recrystallization.