EVOLUTION OF THE MICROSTRUCTURAL PARAMETERS OF COLD WORK Ti-6-Al-4V ALLOY

The aim of this work is to investigate cold worked Ti-6Al-4V (α+β) alloy. The alloy was examined by X-ray diffraction using Rietveld refinement method. The MAUD software (Materials Analysis Using Diffraction) was used to analyze the microstructural parameters evolution (crystallite size, root mean square strain (r m s) and dislocations density (ρ). The Crystallite size is smaller in the β-phase compared to the α-phase and the microstrain with the dislocations density are higher in the α-phase than that the β-phase in the as received material. The microstructural parameters of  Ti-6Al-4V alloy exhibit typical values of cold deformation state. The results show a reduction in the crystallite size (coherent diffraction domains) as a function of the deformation from 520 to 210 Ȧ in the α-phase. Consequently, the root mean square strain increase from 0.0005 to 0.0032 and the dislocations density increase from 2.92 E +10 to 4.6 E +11 m -2 after 85 % thickness reduction.